U.S. PATENT AND TRADEMARK OFFICE
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U.S. Patent Classification System - Classification Definitions
as of June 30, 2000
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Class 330
AMPLIFIERS
Class Definition:
(A) This is the generic class for amplifiers as limited by
the definition of amplifiers as it appears in the Glossary
below.
(B) Included are amplifiers having all types of active
elements (or amplifying devices, the term used in this class)
as for example vacuum tubes, gas tubes, semiconductors,
magnetic type saturable reactors, masers, etc.., as set forth
in the specific subclasses in the schedule for the class.
Specific types of vacuum tube amplifier devices included are,
traveling wave type tubes, secondary emission type tubes,
electron beam tubes, magnetrons, etc..
(C) Included are amplifier systems having plural amplifier
channels, cascade amplifiers, push-pull amplifiers and other
amplifiers having plural amplifier devices. Also included
are amplifiers with plural signal sources or plural loads, as
for example sum or difference amplifiers which have plural
sources.
(D) Amplifiers including the means coupling the signal source
to the amplifier or coupling the amplifier to the load or
between cascaded stages are also included herein. Such
coupling means include those of the distributed parameter
type, resonant tuned circuits, filters, coupling designed to
pass a broad band, D.C.. coupled circuits, potentiometer
means for volume control, equalizers, circuits for volume
control, etc..
(E) Amplifiers combined with tone control means are also
included herein as indicated in D above for the type included
in the amplifier coupling means, also included herein are
those tone control amplifiers relying on signal feedback
means to effect the tone control.
(F) Amplifiers combined with amplitude (volume) control means
whether by manual control, by control of an electrode D.C..
bias, as in gain control, or by controlling a variable
impedance means for the signal transmission path of the
amplifier are also included herein.
(G) Amplifiers combined with power supply means for such
amplifier are also included herein, as well as means to
control the voltage or current of such means.
(H) Amplifiers combined with structural features of the
amplifier or the amplifier circuit elements including
structure of the amplifier device, capacitors, transformers,
etc..
(I) Amplifiers having signal feedback means.
LINES WITH OTHER CLASSES AND WITHIN THIS CLASS
A. TWO-TERMINAL NEGATIVE RESISTANCE NETWORKS
Such networks containing an active element (amplifying
device) are not classified in this class, but classified
elsewhere. (See References to Other Classes, below.)
B. LIMITERS
Passive networks which limit the signal amplitude voltage or
current are classified elsewhere. Miscellaneous limiting
circuits with active device elements are classified
elsewhere. (See References to Other Classes, below.)
C. MISCELLANEOUS ELECTRONIC TUBE CIRCUITS
Circuits including electron tubes (other than the limiters
discussed above) in which the signal output is not a
substantial replica of the input signal, are classified
residually elsewhere. Examples of such tube circuits are
wave conversion circuits, miscellaneous pulse generating
systems, and electronic tube gating circuits. (See
References to Other Classes, below.)
D. SATURABLE REACTOR CIRCUITS (MAGNETIC AMPLIFIERS)
Such circuits which control voltage or current and are not
classifiable herein (as for example, where the A.C. power
supply current is not removed from the signal output by
filtering or other means) are classified elsewhere.
Saturable reactor circuits for wave shaping, switching, pulse
production, etc.., analogous to similar electronic tube
circuits are classified elsewhere with nonlinear reactor
systems, and computers using magnetic amplifiers are also
classified elsewhere. (See References to Other Classes,
below.)
E. NONLINEAR REACTOR CIRCUITS:
Where a nonlinear capacitor serves as the active element or
amplifying device in a circuit which switches, shapes a wave,
or produces pulses and is not provided for elsewhere
classification is in Class 307. So called amplifier circuits
including a nonlinear capacitor as the amplifying device,
which have an A.C. source where the claims do not provide a
filter to remove the A.C. source from the output or where a
demodulator is claimed and no filter or other means to remove
the A.C. power supply from the signal output circuit is
disclosed, are excluded from this class. (See References to
Other Classes, below.)
F. MISCELLANEOUS TRANSISTOR CIRCUITS:
Transistor circuits which are not amplifiers or not combined
with an art device or in a system specifically provided for
in some class, are classified elsewhere. Such art as
miscellaneous transistor wave shapers, gating circuits,
limiters, and pulse producers are classified therein. (See
References to Other Classes, below.)
G. AMPLIFIER COMBINED WITH SPECIFIC SOURCE OF SIGNAL ENERGY:
This class does not provide for combinations of amplifiers
with a specific source of electric signal, such as a
microphone which limits the system to use with a particular
art even though the source is claimed by name only.
Similarly, where the source is claimed by characteristics
specific to the art device as for example, "a source of
speech signals" classification is not in this class. However,
classification is in this class where the source is claimed
by its electrical characteristics not specific to the source
device, as for example, "a high impedance source of
electrical signal". Where the specific source, or details
thereof are claimed, classification is with the art device so
identified. (See References to Other Classes, below.)
Generator Or Oscillator Claimed By Name Only
The terms generator or oscillator in claims, where they
appear as sources of signal energy without further
qualification except by their electrical characteristics such
as impedance, reactance, etc.., are treated as generalized
sources of signal energy, and classification is with
amplifiers except where specific details of the generator or
oscillator are claimed; in such cases classification is with
the type of generator claimed or with oscillators. (See
References to Other Classes, below.)
H. AMPLIFIERS COMBINED WITH SPECIFIC LOAD:
Where the load is claimed, broadly, or by name only as a
specific electrical art device, as for example, as a
loudspeaker, classification is not in this class but with the
load art device claimed. Where characteristics of the load
device are claimed, which are peculiar to the disclosed
electrical art device or to a specific type of electrical art
device, classification is with the load art device
established in the claim. Subject matter wherein general
electrical characteristics of the load are claimed, as for
example, "a load having a variable impedance," is classified
in this or indented subclasses. (See References to Other
Classes, below)
I. OSCILLATOR AS A LOAD FOR AN AMPLIFIER
Subject matter wherein an amplifier is combined with an
oscillator as load for the amplifier is classified with
amplifiers when the oscillator is claimed by name only; where
specific details of the oscillator are claimed,
classification is elsewhere. (See References to Other
Classes, below.)
J. REPEATERS:
Devices known in the art as repeaters which are in effect
two-way amplifiers are not classified in this class but are
classified elsewhere. (See References to Other Classes,
below.)
K. AMPLIFIERS COMBINED WITH LONG LINE TRANSMISSION MEANS OR
DISTRIBUTED PARAMETER ELEMENTS, AND AMPLIFIERS COMBINED WITH
WAVE FILTERS, EQUALIZERS OR ATTENUATORS:
Such subject matter is classified herein even though the
amplifier is claimed by name only, if some detail of the
co-operation of the amplifier with the passive network
(coupling) is claimed. (See References to Other Classes,
below.)
L. COMPANDERS INCLUDING AMPLIFIERS:
Systems including means to compress a signal wave, an
electrically long transmission line and means to expand the
signal wave are not classified herein even when they include
details of an amplifier. Companders are classified elsewhere.
Amplifiers with compressor or expander means alone not
involving a complete compander system are classified herein.
Such subcombinations involving connection or maintenance of a
predetermined condition of the transmission line are
classified elsewhere. Where such connection is of an
amplifier condition classification is herein. (See
References to Other Classes, below.)
M. SYSTEMS INCLUDING PILOT CONTROL MEANS:
Amplifiers including a pilot control frequency component in
the signal source which is used to control the amplifier are
classified herein.
Transmission Lines Combined With Pilot Control - Such subject
matter is classified elsewhere when provided with an
auxiliary line for the pilot control signal; for those
systems in which the pilot control signal is combined with
the signal to be transmitted; with an amplifier which is
controlled must correct or maintain a predetermined condition
of the transmission line for classification elsewhere.
Otherwise classification is herein.
Pilot Frequency Controlled Repeaters - Such subject matter is
classified elsewhere.
N. GAS OR VAPOR TUBE CIRCUITS IN OTHER CLASSES:
Gas or vapor tube circuits are classified elsewhere. (See
References to Other Classes and Within This Class.)
O. TRAVELING WAVE TUBES AND CIRCUITS:
Classification of traveling wave tube amplifiers is in this
class when it includes the output or load circuit.
Classification is otherwise where no load or output circuit
is claimed and the circuit means which may be involved are an
integral part of the tube. Oscillators including a traveling
wave tube are classified elsewhere. (See References to Other
Classes, below.)
P. AMPLIFIER AND A DETECTOR OR SUPERHETERODYNE CONVERTER AND
AN AMPLIFIER:
Such subject matter involves a subcombination peculiar to
radio receivers and is classified elsewhere with radio
receivers or in appropriate subclasses for a demodulator with
amplifier. When an amplifier and a detector are claimed and
the detector is claimed merely as a means to develop a
control signal and not for the purpose of detecting the
intelligence signal as a function of a receiver,
classification is herein and not in receivers. Where the
same tube serves both as a detector and an amplifier
classification is not in this class but elsewhere.
Demodulators, depending again upon the type of demodulator
involved, are classified elsewhere. Combinations which
comprise a reflex amplifier or a superregenerative detector
are classified elsewhere. (See References to Other Classes,
below.)
Q. VOLTAGE MAGNITUDE CONTROL SYSTEMS:
Voltage magnitude control (for single source energy systems)
such as line voltage control, etc.., in general, is
classified elsewhere and includes current or load regulation,
current and voltage limiting systems, transformer and
impedance systems for the purpose. See LIMITERS, above.
(See References to Other Classes, below.)
R. SYSTEM OR DEVICES CLOSELY RELATED TO OR ANALOGOUS TO
AMPLIFIERS:
See References to Other Classes, below.
S. SYSTEMS UTILIZING AMPLIFIERS:
The great majority of electrical control or signaling systems
utilize amplifiers such as are classified herein or closely
related devices (as where the waveform of the input is not
retained in the output). Such systems include, also,
mechanical systems with electrical control means. In view of
such widespread use no attempt is made to list the classes of
all or a large number of systems utilizing amplifiers.
Systems involving amplifiers in combinations where the
amplifier is invariably present, involve few additional
elements, or wherein the amplifier is usually an important
component of the combination are classified elsewhere.
Also see References to Other Classes, below.
T. ELEMENTS OR CIRCUIT NETWORKS COMMONLY USED IN AMPLIFIERS
OR AMPLIFIER SYSTEMS:
See References to Other Classes, below.
REFERENCES TO OTHER CLASSES
SEE OR SEARCH CLASS:
174, Electricity: Conductors and Insulators, 32 for
shielding means. (See Lines With Other Classes, T, "Elements
or Circuit Networks Commonly Used in Amplifiers," above.)
250, Radiant Energy, appropriate subclasses, for the
detection of invisible radiant energy or the testing of
materials by invisible radiant energy, 200 for photocell
circuits and apparatus, particularly subclass 214 for
photocell controlled circuits including electron tube
circuits. (See Lines With Other Classes, S, "Systems
Utilizing Amplifiers," above.)
257, Active Solid-State Devices (e.g., Transistors,
Solid-State Diodes), for active solid state devices, per se.
(See Lines With Other Classes, T, "Elements or Circuit
Networks Commonly Used in Amplifiers or Amplifier Systems, "
above.)
307, Electrical Transmission or Interconnection Systems, for
saturable reactor circuits for wave shaping, switching, pulse
production, etc.., analogous to similar electronic tube
circuits; 401 for nonlinear reactor systems. So called
amplifier circuits including a nonlinear capacitor as the
amplifying device, which have an A.C. source where the claims
do not provide a filter to remove the A.C. source from the
output or where a demodulator is claimed and no filter or
other means to remove the A.C. power supply from the signal
output circuit is disclosed is classified in subclasses 401+.
(See Lines With Other Classes, D, "Saturable Reactor
Circuits (Magnetic Amplifiers)." E, "Nonlinear Reactor
Circuits." and R, "System or Devices Closely Related to or
Analogous to Amplifiers," above.)
313, Electric Lamp and Discharge Devices, appropriate
subclasses for the structure of vacuum tubes and gas and
vapor tubes. See the class definition of Class 313. (See
Lines With Other Classes, T, "Elements or Circuit Networks
Commonly Used in Amplifiers", above.)
315, Electric Lamp and Discharge Devices: Systems, for gas or
vapor tube circuits in other classes; see the classes
specified in the Notes thereto for gas or vapor tube
circuits. (See Lines With Other Classes, N, "Gas or Vapor
Tube Circuits in Other Classes.")
315, Electric Lamp and Discharge Devices: Systems, subclass
3.5, 3.6 or 39.3 for classification otherwise where no load
or output circuit is claimed and the circuit means which may
be involved are an integral part of the tube. (Lines With
Other Classes, O, "Traveling Wave Tubes and Circuits")
323, Electricity: Power Supply or Regulation Systems for
passive networks which limit the signal amplitude voltage or
current. (Lines With Other Classes, B, "Limiters.")
323, Electricity: Power Supply or Regulation Systems, for
circuits which control voltage or current. (See Lines With
Other Classes, D, "Saturable Reactor Circuits (Magnetic
Amplifiers.")
323, Electricity: Power Supply or Regulation Systems, for
voltage magnitude control (for single source energy systems)
such as line voltage control, etc.., in general (see the
class definition). (Lines With Other Classes, "Voltage
Magnitude Control Systems")
324, Electricity: Measuring and Testing, 123 for amplifiers
with meters.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 309 for miscellaneous limiting
circuits with active device elements.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 100 for wave conversion circuits,
subclasses 291+ for miscellaneous pulse generating systems,
and subclasses 365+ for electronic tube gating circuits.
(Lines With Other Classes, C, "Miscellaneous Electronic Tube
Circuits.")
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for transistor
circuits which are not amplifiers or not combined with an art
device or in a system specifically provided for in some
class. (See Lines With Other Classes, F, "Miscellaneous
Transistor Circuits.")
329, Demodulators, appropriate subclasses for a demodulator
with amplifier. (See Lines With Other Classes, P, "Amplifier
and a Detector or Superheterodyne Converter and an Amplifier"
and S,"Systems Utilizing Amplifiers", above.)
329, Demodulators, where the same tube serves both as a
detector and an amplifier, depending upon the type of
demodulator involved. (Lines With Other Classes, P,
"Amplifier and a Detector or Superheterodyne Converter and an
Amplifier")
331, Oscillators, are in the most common types, in a sense,
merely positive feedback amplifiers without an input, and
therefore the circuits, structures, and problems are often
closely related to those of amplifiers. (See Lines With
Other Classes, R, "System or Devices Closely Related to or
Analogous to Amplifiers, " above.)
331, Oscillators, where specific details of the generator or
oscillator are claimed; in such cases classification is with
the type of generator claimed or with oscillators. (See
Lines With Other Classes, G, under "Generator or Oscillator
Claimed by Name Only," and I, "Oscillator as a Load for an
Amplifier, " above.)
331, Oscillators, for oscillators including a traveling wave
tube; subclass 82 for traveling wave type. (Lines With
Other Classes, O, "Traveling Wave Tubes and Circuits")
332, Modulators, appear, usually as no more than amplifiers
which have an input source in addition to the signal (i.e.,
the carrier). (See Lines With Other Classes, R, "System or
Devices Closely Related to or Analogous to Amplifiers",
above.)
333, Wave Transmission Lines and Networks, appropriate
subclasses, particularly 24, for passive wave filters and
coupling networks. (See Lines With Other Classes, T,
"Elements or Circuit Networks Commonly Used in Amplifiers or
Amplifier Systems," above.)
333, Wave Transmission Lines and Networks, 213 for networks
containing an active element (amplifying device). (See Lines
With Other Classes, A, "Two-Terminal Negative Resistance
Networks," above.)
333, Wave Transmission Lines and Networks, subclass 14 for
companders. Subcombinations involving connection or
maintenance of a predetermined condition of the transmission
line are classified in Class 333. (See Lines With Other
Classes, L, "Companders Including Amplifiers.")
333, Wave Transmission Lines and Networks, subclass 15, when
provided with an auxiliary line for the pilot control signal,
subclass 16 for those systems in which the pilot control
signal is combined with the signal to be transmitted and also
subclass 16 with an amplifier which is controlled must
correct or maintain a predetermined condition of the
transmission line. (Lines With Other Classes, M, under
"Transmission Lines Combined With Pilot Control," above.)
333, Wave Transmission Lines and Networks, for electric wave
transmission systems, passive wave transmission networks,
passive coupling networks and terminating networks, smoothing
type wave filters, networks including a wave transmission
device, passive networks for producing an output wave,
systems including active elements, and wave traps using long
line elements. (Lines With Other Classes, K, "Amplifiers
Combined With Long Line Transmission Means or Distributed
Parameter Elements, and Amplifiers Combined With Wave
Filters, Equalizers or Attenuators")
334, Tuners, appropriate subclasses for tuners, per se. (See
Lines With Other Classes, T, "Elements or Circuit Networks
Commonly Used in Amplifiers, " above.)
336, Inductor Devices, appropriate subclasses for the
structure of transformers and inductor devices, generally.
(See Lines With Other Classes, T, "Elements or Circuit
Networks Commonly Used in Amplifiers or Amplifier Systems, "
above.)
359, Optics: Systems (Including Communication) and Elements,
109 for light wave communications. (See Lines With Other
Classes, S, "Systems Utilizing Amplifiers," above.)
361, Electricity: Electrical Systems and Devices, 196 for
electric circuits including transistors, subclasses 199+ and
205 for electric circuits including space discharge devices
combined with relays as the load therefor, and subclass 204
for electric circuits including saturable reactors, wherein
the transistor, space discharge, or saturable reactor circuit
may be an amplifier. (See Lines With Other Classes, S,
"Systems Utilizing Amplifiers", above.)
361, Electricity: Electrical Systems and Devices, 271 and
500+ for capacitor structure, per se. (See Lines With Other
Classes, T, "Elements or Circuit Networks Commonly Used in
Amplifiers or Amplifier Systems," above.)
379, Telephonic Communications, 338 for devices known in the
art as repeaters which are in effect two-way amplifiers.
(See Lines With Other Classes, J, "Repeaters," above.)
381, Electrical Audio Signal Processing Systems and Devices,
111 for miscellaneous systems which include combinations of
amplifier and loud speaker or microphone and amplifier which
limits the system to use with a particular art even though
the source is claimed by name only; for distribution
systems, involving a central broadcasting system from which
programs are distributed to local stations where the programs
are amplified and reproduced; also for where the load is
claimed, broadly, or by name only as a specific electrical
art device, as for example, as a loudspeaker. (See Lines
With Other Classes, G, "Amplifier Combined With Specific
Source of Signal Energy," H, "Amplifiers Combined With
Specific Load," and S, "Systems Utilizing Amplifiers,"
above.)
455, Telecommunications, 130 for radio receivers which may
be limited to an amplifier and a detector; subclass 351 for
portable radio receivers. (See Lines With Other Classes, S,
"Systems Utilizing Amplifiers," above.)
455, Telecommunications, appropriate subclass, particularly
subclass 335, where the same tube serves both as a detector
and an amplifier. Class 455, subclass 342, includes
combinations which comprise a reflex amplifier or subclasses
336+ for combinations which comprise a superregenerative
detector. (Lines With Other Classes, P, "Amplifier and a
Detector or Superheterodyne Converter and an Amplifier")
455, Telecommunications, 130 for a subcombination peculiar
to radio receivers classified with radio receivers. (See
Lines With Other Classes, P, "Amplifier And a Detector or
Superheterodyne Converter And An Amplifier.")
505, Superconductor Technology: Apparatus, Material,
Process, 150 for high temperature (T[subscrpt]c[end
subscrpt] 30 K) superconducting device; and particularly
subclass 180 for maser-type amplifying device, or subclasses
191+ for semiconductor device. (See Lines With Other Classes,
R, "System or Devices Closely Related to or Analogous to
Amplifiers, "S, "Systems Utilizing Amplifiers", and T,
"Elements or Circuit Networks Commonly Used in
Amplifiers,"above.)
GLOSSARY:
ACCEPTOR IMPURITY OR ACCEPTOR
A material which when added to a semiconductor material in
minute quantities, as an impurity, induces hole conduction,
generally causing the semiconductor to be one of "P-type
conductivity".
ACTIVE NETWORK
A network containing a source of energy, or a sink of energy
(i.e., a device for absorbing or dissipating energy other
than that accounted for by the resistance of the components
of the networks). Merely dissipating the heat generated by a
resistance will not cause the resistance to be an active
element. See Amplifying Device.
AMPLIFIER
Electric circuit means wherein a variable electrical current
or voltage input signal is applied to an electrical
amplifying device to control a source of electrical energy
applied to the same device and from which is derived an
output signal of substantially the same wave form as the
input signal and substantially linearly related thereto.
AMPLIFIER CHANNEL OR CHANNEL
A part of an amplifier system in which a single signal path
may be traced from a source to a load, and which path
includes an amplifier as defined above. Such channel may be
a cascade amplifier.
AMPLIFYING DEVICE
An electrical transducer of the active type wherein the
electrical energy supplied by one system (power supply) is
controlled by the electrical energy supplied by another
system (signal source) limited to the active transducer
device element itself such as a vacuum tube, transistor,
controllable gas tube, saturable reactor, variable resistive
element, etc.. See Active Elements.
AMPLITUDE LIMITER
A means in a circuit to limit the amplitude of the electrical
voltage across it or the current in it to a value below or
above a fixed predetermined value, particularly the former.
ANODE
An electrode which acts as the positive terminal of an
electric discharge or which acts as the positive terminal of
an electric field to cause a discharge or accelerate the
electrons in an electric discharge.
ATTENUATOR
Devices and networks consisting of one or more elements which
exhibit only a positive resistance effect and which reduce
the intensity of the energy passing through the device by
dissipation, (1) the elements being proportioned to permit a
change in their value to control the energy loss while
maintaining substantially constant input and/or output
impedance of the device, and/or (2) the elements being
proportioned to permit the device to be inserted in the
circuit to provide an energy loss without introducing any
reflections in the circuit, and/or (3) the elements being
combined with a long line or long line element, and/or (4)
the device or network having an impedance equal to the
impedance of a specified long line, and/or (5) the device or
network is claimed as being particularly modified for use
over a frequency band so that its characteristics are
particularly related to frequency.
AUXILIARY GRID
Any grid, of an electronic tube other than the signal input
grid.
BALANCED CIRCUIT
A circuit having its conductors electrically symmetrical with
respect to a reference potential plane (e.g., ground). The
potential between the two sides and ground are equal and of
opposite sign. For example, a horizontal two-wire line may
be a balanced line. See Push-Pull Stage.
BASE ELECTRODE
See the definition of point contact or junction transistor
above.
BIAS, BIAS VOLTAGE, BIAS CURRENT
In an amplifying device, usually, a steady D.C.. voltage or
current applied between two electrodes usually referred to
the input electrodes to form an electric reference means for
the control means, which influences the current flow of an
electronic tube or semiconductor device or the flux
relationships of a magnetic saturable reactor. See also Bias
Control and Power Supply.
BIAS CONTROL
Control, as defined above applied to control of bias voltage
or current of an amplifying device. This is distinguished
from signal feedback in that the bias control voltage or
current has a smoothed average value which adds to or
subtracts from the bias voltage or current and is unlike the
signal feedback voltage which varies instantaneously with the
signal at the point from which it is derived. See also,
Bias, Bias Voltage or Bias Current.
CASCADE AMPLIFIER
A series of amplifiers wherein the input for each amplifier
except the first (to which the electric signal source is
connected) is coupled from the output of the prior
amplifier.
CATHODE OR CATHODE ELECTRODE
The negative electrode of the two electrodes of an electronic
tube between which an electric discharge occurs (for negative
charge carrier particles); in a vacuum tube the electrode
which emits the electrons and is negatively charged with
respect to the electrode which collects the electrons.
CATHODE-HEATER
A filament in proximity to an indirectly heated cathode with
terminals designed to receive a source of power to heat the
cathode to its electron emitting temperature.
CATHODE IMPEDANCE
The impedance from the cathode of an electronic tube to
ground or a reference potential.
CHARGE CARRIER PARTICLE
A charged particle of matter involved in a flow of space
current (electric discharge) and by means of which such
current flows (current flow other than an electromagnetic
wave propagated in open or confined space). Such charge
carrier particles may be ions of a gas or charged atomic
particles such as electrons.
COLLECTOR ELECTRODE
See the definition of point contact or junction type
transistor below.
COMPRESSOR OR VOLUME COMPRESSOR
A device that compresses the volume range, as in recording
sound, radio-telephone transmission, etc.. In compressing
the signal volume range the amplification of large signals is
reduced and of small signals is increased.
CONFIGURATION
The arrangement of electrodes of a transistor as input and
output electrodes, e.g., common base configuration, where the
base is included in both the input and output circuits of a
transistor amplifier.
CONTROL
A selective adjustment of an element of an amplifier to vary
the operation of the amplifier in a desired manner, or the
characteristic of a part of the amplifier whereby in response
directly to signal, or by means of a developed voltage or
current in response to the signal, or by a voltage from some
outside source, the impedance characteristics of a circuit
element, or the electrical characteristics (bias or
energizing voltage) of an amplifying device are automatically
altered to change the operation of the amplifier in a
predetermined manner. Such control may be by a nonlinear
impedance element alone in a biasing or power supply circuit.
The term control has not been applied in this class, when a
nonlinear impedance element is in the signal path and affects
the signal only, without any control from a separate path
being applied to vary such impedance.
CONTROL ELECTRODE
An electrode designed to influence or control the discharge
current flowing between other electrodes. It may depend for
its effect on either its electrostatic effect or on the
current flow thereto. The most common types of control
electrodes are the signal control grid, or the gain control
electrode or grid.
CONCENTRIC LINES
A transmission line in which one conductor extends within a
second hollow conductor.
CONTROL GRID
A control electrode having grid construction.
D.C. COUPLING
A signal coupling network including a D.C.. conductive path.
In a four terminal network such paths must be traced between
terminals on the circuits to and from which the coupling is
made which vary in voltage with the signal (this excludes
D.C.. paths limited to ground leads or D.C.. shunt paths).
D.C. PATH OR D.C. CONDUCTIVE PATH
A path for current in a network which can conduct D.C..
current.
DELAY NETWORK
Networks including significant structure for retarding wave
energy a predetermined period of time over a range of
frequencies.
DIODE
Refers to any electronic tube, solid element, semiconductor,
barrier layer device or other current carrier means limited
to two electrodes and without additional magnetic or
electrostatic means to influence the current flow, and which
has marked unidirectional current characteristics.
DIRECTLY HEATED CATHODE OR FILAMENTARY CATHODE
A filament designed to have its terminals connected to a
source of current, the filament being heated by the current
passing through it and effective to emit electrons, designed
to serve as a cathode of an electronic tube as defined
above.
DISCHARGE PATH
The path of the free electrical charge carrier particles
between the electrodes of an electronic tube.
DISTRIBUTED PARAMETER CHARACTERISTICS
A conductor or conductive means designed to operate at
microwave or other high frequencies, so that the conductive
means exhibits both distributed capacitance and distributed
inductance at such frequencies.
DISTRIBUTED PARAMETERS
When the impedance of a transmission device or line at the
operating frequency or band of frequencies is due primarily
to the parameters of the device or line itself, and in
considering the inductance, capacitance and resistance of the
device or line they must be considered as mixed together and
spread out along the device or line rather than being
considered as in separate discrete lumps or devices as in the
case of simple series and parallel circuits, the transmission
device or line may be said to have distributed parameters.
Examples of circuits with distributed parameters include
telephone, telegraph and power lines for high frequency
energy.
DONOR IMPURITY OR DONOR
A material which when added to a semiconductor in minute
quantities, as an impurity, induces electron conduction,
generally causing the semiconductor to become one of "N-type
conductivity".
ELECTRIC CARRIERS OF A TRANSISTOR
Current flow in a transistor may be by negative carriers
(electrons) or positive carriers (holes).
ELECTRIC DISCHARGE
The flow of current between two spaced electrodes at
different potentials or the charge carrier particles
conveying the current from one spaced electrode to the
other.
ELECTRIC SIGNAL SOURCE OR SIGNAL SOURCE
The source of electrical signal energy to be amplified or the
source of electrical signal energy which controls the
electric power supply applied to the amplifying device.
ELECTRICAL CIRCUIT
An electrical network providing one or more closed paths.
ELECTRICAL NETWORK OR NETWORK
An arrangement of electrically connected electrical elements
and/or devices which are capable of carrying electric A.C. or
D.C.. current. Note. A network does not define the
structure in space of the network elements or their
arrangement in space relative to each other; it merely
defines the elements or devices broadly by type as to the
electrical function they perform and the electrical
connections which will carry current between such elements
and/or devices.
ELECTRODE
(1) In a vacuum tube, electronic tube or in any discharge
device, the conductive elements between which the electric
discharge takes place, and to which the power supply is
applied; any additional conductive means placed in proximity
to the electric discharge and/or other electrodes to affect
electrostatically the discharge or the potentials of the
electrodes with which they are in proximity. (2) In a
magnetic amplifying device or in a resistive amplifying
device, (including semiconductive devices) the terminals of
windings which influence the operation of the magnetic device
or the resistor or semiconductor terminals by means of which
electric current may flow in or out of the resistor or
semiconductor or by means of which a potential may be applied
to the resistor or semiconductor.
ELECTROMECHANICAL TRANSDUCER
Means to convert the electric signal to mechanical vibrations
and means further to convert the mechanical vibrations back
to electric signals, such means generally serving as either
time or phase delay means or means to determine the
transmission frequency of the coupling network.
ELECTRONIC TUBE
An electric space discharge device, that is, a device in
which electricity flows from one electrode to another by
means of free electrical charge carrier particles traveling
in a vacuum, gas or vapor; included are electric space
discharge devices (also called electronic tubes) which
operate in the open, i.e., not in an enclosed envelope. The
electrical charge carrier particles may be of any type,
usually electrons for vacuum tubes or charged ions for gas or
vapor tubes.
EMITTER ELECTRODE
See the definition of point contact or junction type
transistor in this Glossary.
EQUALIZER
Networks with attenuation or attenuation and phase distortion
characteristics which vary over a frequency range for use in
a wave transmission system for modifying the attenuation or
attenuation and phase characteristics of the wave energy as a
function of frequency.
EXPANDER OR VOLUME EXPANDER
A device that expands the volume range, as in recording
sound, radio-telephone transmission, etc.. In expanding the
signal volume range, the amplification of large signals is
increased, and the amplification of small signals is reduced.
Expanders are used generally to restore a signal after
compression.
GRID
Is used in the conventional sense referring to the intended
use and structure of the element in an electronic tube,
particularly in a vacuum tube.
FILAMENT
A wire, ribbon, or rod conductive member.
FILTER
A frequency selective means.
FREQUENCY RESPONSIVE MEANS
Circuit means which acts on the signal to affect some
frequency component of the signal differently from any other
frequency components of the signal, for example, a tuned
circuit or filter circuit which eliminates a frequency
component, or an equalizer which emphasizes the signal
amplitude of some frequency or frequency range of the signal
with respect to others (e.g., tone control). See also,
Frequency Selective Means, below.
FREQUENCY SELECTIVE MEANS
Network means composed of some reactive elements which permit
the passage of certain frequency components or a frequency
component and block others. See also, Frequency Responsive
Means.
GAIN
The ratio of the amplifier output power, voltage, or current
to the amplifier input power, voltage or current.
GAIN CONTROL ELECTRODE
An electrode designed, together with the electron tube in
which it is incorporated, to receive a D.C.. control voltage
(other than the signal but which is usually derived from the
signal), whereby changes in the control voltage change the
gain of the tube.
GAS OR VAPOR TUBE
An electric discharge device which depends, for its
operation, at least in part, upon ionization of a gas or
vapor.
GRID OR GRID ELECTRODE
An electrode having one or more apertures therein, usually
formed of open-work material such as wire mesh, etc.., and
usually used as the signal or control electrode, or auxiliary
electrode of an electron tube.
IMPEDANCE MATCHING NETWORK
Coupling networks which include one or more impedance
elements construed or proportioned to substantially eliminate
the reflected wave energy between the network and at least
one of the connected circuits caused by impedance
differences.
INDIRECTLY HEATED CATHODE (equiptential cathode)
A cathode designed to be heated to its emitting temperature
by a separate heating element.
INPUT CIRCUIT OR COUPLING
The circuit or network of an amplifier extending from the
source of electrical signal to the input electrodes of the
amplifier, which may include the source of electrical
signal.
INTERELECTRODE CAPACITANCE
The capacitive reactance for signal flow between any two
electrodes of a vacuum tube, transistor or similar device
inherent in their relationship to each other
electrostatically and which for certain frequencies and
voltages forms a path for the signal current usually
detrimental to the operation of the circuit.
INTERELECTRODE IMPEDANCE
An impedance between electrodes of a vacuum tube, transistor,
or similar device inherent in its structure, and manner and
frequency of operation. This term is generic to
inter-electrode capacitance above; and includes also input
conductance caused by the transit time of electrons, etc..
INTERSTAGE CIRCUIT OR COUPLING
The electrical circuit or network by means of which the
output signal from the output electrodes of the amplifying
device of one stage of a cascaded amplifier is conveyed to
the input electrodes of the amplifying device of the
following stage of the cascade amplifier.
INTRINSIC CONDUCTIVITY
Refers to a semiconductor material which for a certain range
of conditions has its free electron carriers and free hole
carriers in approximate balance, so that the semiconductor
material is neither N- nor P-type. Sufficient change in
temperature or sufficient radiant energy impinging upon such
a body will upset this equilibrium.
JUNCTION IN A TRANSISTOR OR SEMI-CONDUCTOR
The boundary of P-type and N-type semiconductor material.
JUNCTION TRANSISTOR
A transistor comprising two P-N Junctions back-to-back
wherein a region of P- or N-type semiconductor material is
common to both junctions (thus determining an NPN or a PNP
junction transistor, respectively); an emitter electrode
connected to one of the conductivity regions not common to
the two junctions, normally forwardly biased (positive
terminal of bias means to emitter for PNP type and negative
terminal for NPN type); a collector electrode connected to
the other conductivity region but common to the two
junctions, reversely biased (negative terminal of bias means
for the PNP type and positive terminal for the NPN type; and
a base electrode connected to the region common to both
junctions. See definition of Point Contact Transistor, which
operates similarly in many respects.
LECHER LINES
A parallel transmission line with means to tune the parallel
line.
LOAD
The electric device or circuit which utilizes the output
signal derived from the amplifier after the input signal has
controlled the electric power supply by means of the
amplifying device to yield a signal which is a replica of the
input signal but usually of greater amplitude.
LONG LINE
A wave transmission device or line having distributed
parameters and especially designed to propagate electrical
wave energy where the wave length of the transmitted energy
is relatively short when compared with the length of the
transmission line or device. The impedance of a long line is
practically fixed by the constants of the line itself. The
length of the transmission line or device may be a multiple
or a fraction of a wave length, e.g., 1/4, 1/2, etc.., or
otherwise have its length proportioned to the wave length of
the energy with which it is to be used.
LONG LINE ELEMENT
A circuit element having distributed parameters, such as a
resonator, or a wave guide. A long line element may be a
part of a long line wave transmission device or used in a
network with other circuit elements of the lumped parameter
type, for example, as in the case of delay networks,
impedance matching networks, wave filters.
LOOP PATH
In an amplifier having signal feedback, the path of the
signal from the input point where the signal feedback is
applied forward through the amplifier to the point in the
circuit from which the signal feedback is derived through the
signal feedback path to the aforesaid input point.
MAJORITY CARRIERS
See the definition of N- or P-type conductivity below.
MINORITY CARRIERS
See the definition of N- or P-type conductivity below.
NEGATIVE FEEDBACK
Signal feedback having at least some component thereof in
opposite phase with the signal at the point where the signal
feedback is applied.
N-TYPE CONDUCTIVITY
The characteristic of a semiconductor material, usually
imparted by the addition of impurities of the "donor" type,
of an excess of free electrons over holes (free positive
charges) at any time at room temperature, such negative
charge carriers or electrons being referred to as majority
carriers for current flow in such material, and holes as
minority carriers for such current flow.
NEUTRALIZATION MEANS
Circuit means to eliminate, mitigate, or lessen undesirable
effects of inter-electrode capacitance or inter-electrode
impedance and which may include the input and/or output
impedance of the amplifying device involved (such input or
output impedance includes the inter-electrode impedance of
the input or output electrodes).
NONLINEAR IMPEDANCE OR DEVICE
An impedance or device, which may be reactive or resistive or
a combination of both and having the characteristic that for
changes in voltage or current, the relationship of the
voltage drop across the impedance or device, or the voltage
applied across the impedance or device to the current flowing
through it, is nonlinear.
OUTPUT CIRCUIT OR COUPLING
The circuit or network of an amplifier extending from the
output electrodes of the amplifier to the load device, which
may include the load.
PARASITIC REACTANCE, IMPEDANCE, CAPACITANCE, OR INDUCTANCE
Impedance characteristics of capacitive or inductive nature
which are exhibited by conductive elements or conductive
parts of a circuit at only high frequencies in a circuit
designed for operation over a wide band and are inherent in
the construction of such element or part. The presence of
such reactances is undesirable and generally detrimental to
the proper operation of the circuit. When a parasitic
reactance is used as though it were a predetermined lumped
reactance as in the case of the distributed capacitance of a
coil being used to resonate therewith at a particular
frequency; the distributed capacitance or other parasitic
reactance is treated, for classification purposes, as though
it were a predetermined lumped reactance in the circuit.
Inter-electrode capacitances similarly involved in amplifiers
as part of a tuned circuit are similarly treated.
PASSIVE NETWORK
A network containing no source of energy and in which no
energy is dissipated other than that accounted for by the
resistance of the components of the network.
PHASE SHIFT
Used to designate the change in phase relation between
voltage and current of the same wave energy, or between the
voltages or the currents of different wave energy of the same
frequency.
POSITIVE FEEDBACK
Signal feedback having at least some component thereof in
phase with the signal at the point in the amplifier circuit
where the signal feedback is applied.
POTENTIOMETER
A network which permits the division of a voltage applied
across it, including adjustable means to select a particular
division of the voltage applied across the network.
POWER SUPPLY
The source of electrical energy applied to an amplifying
device which is controlled by the electric input signal. The
term is used herein generically to include also a cathode
heater supply, and bias voltage or current supply.
PLURAL AMPLIFIER CHANNELS
An amplifier system having at least two signal channels each
containing separate amplifiers as defined above (wherein each
amplifier may be a cascade amplifier), such amplifier
channels may be completely separate from each other having
separate and independent sources or loads; usually with some
common control or they may be in parallel, having a common
source and a common load; or the plural channels may be in
branched circuits from separate sources or to separate
loads.
POINT CONTACT TRANSISTOR
A transistor comprising a body of P- or N-type semiconductor
material to which are attached two closely spaced electrodes
connected at sharply defined points to the semiconductor
material and a third electrode, the base relatively remote
from the other electrodes and having a relatively large
contact area (low resistance) for connection to the
semiconductor. In this type of transistor the emitter is
forwardly biased having, in N-type semiconductor material,
the positive terminal of the biasing means connected to the
emitter electrode, and for P-type semiconductor material the
negative terminal of the biasing means connected to the
emitter relative to the base, to inject minority carriers for
the conductivity type semiconductor material (holes for
N-type and electrons for the P-type) and the collector is
biased reversely (having the negative terminal of the biasing
means connected to the collector for N-type material and the
positive terminal for P-type material), relative to the base
so that minority carriers are collected there.
P-TYPE CONDUCTIVITY
The characteristic of a semiconductor material, usually
imparted by "acceptor" type impurities therein, of an excess
of free positive carriers (holes) over free negative carriers
(electrons), such positive carriers or holes being referred
to as majority carriers for current flow in such material and
the electrons as minority carriers for such current flow.
PUSH-PULL STAGE
Includes two amplifiers each as defined above under
"AMPLIFIER", the input electrodes of each of the amplifying
devices of the two amplifiers being balanced to ground or
some other convenient electrical reference plane, the source
of electrical signal being such, and so coupled to the input
electrodes, that at any instant the signal on each input
electrode is substantially equal and opposite in sign to the
signal on the other input electrode; and wherein the signal
on the output electrodes of each of the amplifying devices is
similarly balanced to a convenient electrical reference
plane.
(1) Note. A balanced signal circuit is treated in this
class as a special case of a single source or a single load.
See Balanced Circuit.
(2) Note. A push-pull amplifier is treated in this class as
a single channel, having a single source and a single load.
REACTIVE COUPLING
A coupling network including reactive means which may be
inductive or capacitive.
RECTIFIER
A device with a unilateral current characteristic which
permits the passage of only D.C.. current therethrough, and
which is used to convert A.C. current applied thereto to
D.C.. current.
RESONANT CIRCUIT
A circuit containing both inductive and capacitive reactance
and in which the inductive reactance equals the capacitive
reactance for a particular frequency. The resonant circuit
may be series resonant, where the reactive elements are in
series; or parallel (anti-resonant), where the inductive and
capacitive elements are in parallel. See also, Resonator.
RESONATOR
Devices comprising conductive enclosures, cavities, or wave
transmission line sections of the two terminal type, and
having distributed inductance and capacitance, the line
sections being terminated in other than the characteristic
impedance of the line sections, the devices presenting
resonant characteristics to the existing source of wave
energy. See also Resonant Circuit.
SATURABLE REACTOR
An inductive device having a core and at least one winding
thereon in which the inductance is variable in accordance
with magnetomotive force applied, up to a limiting value
beyond which increased magnetomotive force does not change
the inductance.
SCREEN GRID
A grid electrode placed between the control grid and the
anode of a vacuum tube to reduce inter-electrode
capacitance.
SECONDARY EMISSION ELECTRONIC OR VACUUM TUBE
A tube which depends for its operation, at least in part,
upon the emission of electrons from a body due to collision
of higher energy electrons with the body.
SECONDARY EMISSIVE ELECTRODE
An electrode which emits electrons upon collision with higher
energy electrons. Since all electrodes have this
characteristic, the term applies only to those electrodes
designed to have an electron stream or beam impinge thereon
to emit a stream or beam of secondary electrons.
SEMICONDUCTOR
A material having a specific resistance value of the order of
that of germanium, silicon, selenium, etc.; or insulators
whose specific resistance is reduced in value to the
aforesaid range in operation, by alpha particle or electron
bombardment or other means, so that the insulators operate
broadly as semiconductors in an electrical circuit.
SEMICONDUCTOR AMPLIFYING DEVICE
An amplifying device constructed of a semiconductor with
suitable electrodes for the application of signal current,
power supply energy, and for the derivation of output signal
current.
SIGNAL
A variable electrical current or voltage having
characteristic variations in time, which characteristic
variations are transmitted through an electrical network from
a source in which the signal originates to a load where the
signal is utilized.
SIGNAL ELECTRODE OR SIGNAL GRID
The electrode to which the signal is applied; in the case
where such electrode is a grid electrode, the signal grid.
SIGNAL FEEDBACK
The application of a signal derived from an output electrode,
to an input electrode of an amplifier or a prior stage of an
amplifier. The input and output electrodes of the feedback
may be the same or a common electrode as where vacuum tube
space current flows through an unbypassed cathode impedance
to change the potential on the cathode with respect to the
control grid in accordance with the signal output. (For the
distinction between signal feedback and bias control see the
definition thereof, above).
SIGNAL FEEDBACK PATH
Circuit means to apply a portion of the electrical signal
output of an amplifier to the input of the amplifier
involving a shared impedance for the input and output
circuits.
STABILIZATION MEANS
In an amplifier having a tendency to depart from a
predetermined condition of operation, any circuit means used
to maintain such predetermined condition of operation of the
amplifier. See the definition of Control above.
STRUCTURE
Refers to any details of a circuit element as to the nature
or composition of the material or materials of which it is
made, the form or shape of the element or its parts or the
relationship in space of such elements or parts or such
characteristics of the elements relative to each other.
SWITCH
A device or means for opening or closing an electric
circuit.
THERMALLY RESPONSIVE IMPEDANCE
An impedance element whose impedance value is responsive to
the temperature changes therein by reason of the heat
generated by the current flow therethrough, or the ambient
temperature of the impedance element, or whose impedance
value may be changed by separate electrical control means or
other heat control means.
TRANSISTOR
An amplifying device comprising a semiconductor material to
which contact is made by three or more electrodes.
UNBALANCED CIRCUIT
A circuit having its conductors electrically unsymmetrical
with reference to a potential plane. For example, a
concentric line is ordinarily unbalanced, the outer conductor
being ordinarily connected to ground.
VACUUM TUBE
An enclosed space evacuated of most of its gas wherein an
electric discharge takes place between two electrodes one of
which emits electrically charged atomic particles, generally
electrons and the other electrode collects such particles.
The vacuum tube has at least one additional electrode or
other means to control the flow of charged atomic particles
between the emitter electrode and the collector electrode.
The electric discharge of a vacuum tube is normally an
electron discharge and any discharge of ionized particles is
normally fortuitous and unintended. A vacuum tube is usually
involved in a four terminal network, the input signal being
supplied to two input electrodes usually the grid (control)
and cathode (electron emitting electrode) and the output
circuit normally being comprised of the power supply, the
anode load impedance, the anode, the electron discharge, the
cathode impedance, the load and the output coupling means.
Thus the cathode which is normally present in the output and
input circuits is normally the common electrode. Other
alternative configurations where the input and output
electrodes are not as above, as for example, where the anode
is a common electrode and the cathode is the output
electrode, are known and provided for in the schedule of this
class. The terms for the grid, cathode and anode electrodes
or auxiliary electrodes (as defined below) are referred to
according to the predetermined use usually assigned for them
regardless of the alternative circuit arrangements involved.
The terms input, output, and common electrodes are used as in
these definitions.
WAVE ENERGY
An undulatory disturbance propagated through a medium,
(usually periodic in nature), its displacement varying
periodically with respect to time or distance or both. The
wave may be manifested in electrical, mechanical or
acoustical form. However, in this class the term "wave
energy" refers only to electrical wave energy.
WAVE GUIDE
A transmission device designed to propagate electrical waves
having an electric or magnetic field component extending in
the direction of propagation. The wave guide may be a hollow
dielectric or metal tube, or a solid dielectric rod, the wave
energy being propagated along the interior of the tube or rod
and confined by the walls of the tube or rod.
WAVE TRANSMISSION DEVICE
Any device which is used to guide or constrain electrical
wave energy and to convey the energy from one place to
another. Included are conductors, wave guides, resonant
structures (e.g., cavities, etc..).
SUBCLASSES
Subclass:
1
This subclass is indented under the class definition.
Subject matter wherein the amplifier is combined with other
devices or structures having an added purpose or independent
utility, other than to perfect the amplifier, and in which
the utility of the art device is not destroyed by removal of
the amplifier and which combination is not provided for
elsewhere.
(1) Note. An example of art classifiable in this class and
subclass is an amplifier combined with an automobile
accelerator pedal to control the volume of the amplifier.
The removal of the amplifier does not destroy the utility of
the accelerator pedal (as it would in case of a radio
receiver which included the amplifier or a part thereof).
(2) Note. Subject matter in which a source is claimed by
name only as a specific art device, as for example, a
microphone, is classified with the specific art device and
not with amplifiers. Subject matter, in which the signal
source device may be broadly claimed, not by name, but by
some distinctive identifying feature thereof as, where a
microphone source is claimed as a "means for converting sound
signals", is not classified with amplifiers, but with the
distinctive art device.
(3) Note. The terms generator or oscillator in claims,
where they appear as sources of signal energy without further
qualification except by their electrical characteristics such
as impedance, reactance, etc.., are treated as generalized
sources of signal energy and classification is with
amplifiers except where specific details of the generator or
oscillator are claimed; in such cases, classification is with
the type of generator claimed or with oscillators in Class
331.
(4) Note. Where the load is claimed, even broadly, or by
name only as a specific electrical art device, as for
example, a loudspeaker, classification is not in this class,
but with the load art device claimed. Where characteristics
of the load device are claimed, which are peculiar to the
disclosed electrical art device or to a specific type of
electrical art device, classification is with the load art
device established in the claim.
(5) Note. Subject matter wherein general electrical
characteristics of the load are claimed, as for example, "a
load having a variable impedance", is classified in this
class.
Subclass:
2
This subclass is indented under the class definition.
Subject matter involving means or methods of testing
amplifiers as set forth in the class definition and/or
amplifiers as set forth in the class definition combined with
indicating means to show a condition of the amplifier.
(1) Note. Amplifiers combined with a meter or indicating
means not involving a condition of the amplifier but where
the amplifier is merely an instrument in facilitating such
indication, are not classified in this class and subclass but
in the appropriate subclass of Class 324, Electricity:
Measuring and Testing or Class 340, Communications:
Electrical, unless they are specialized for use in the
testing of a specific electronic art device in which case,
classification is generally with the specific electrical art
device.
SEE OR SEARCH CLASS:
324, Electricity: Measuring and Testing, appropriate
subclasses for electrical measuring and testing. See (1)
Note, above.
340, Communications: Electrical, appropriate subclasses for
systems with signal or alarm indicating means particularly
500. See (1) Note, above.
Subclass:
3
This subclass is indented under the class definition.
Subject matter including at least two amplifying devices each
of which is of a type different from the other.
(1) Note. When each of the amplifying devices is of a type
which is classified in different subclasses of this class
providing for such different types of amplifying devices,
such as subclass 8 for saturable reactor type and subclass 44
for electron beam type, classification is in this subclass.
Where the different types of amplifying devices are types
provided for in coordinate subclasses indented under a major
genus type, classification is not in this subclass, but in
the appropriate subclasses indented under subclass 250.
Diverse type vacuum tube amplifying devices combined in an
amplifier are classified in subclass 3 when each of the
diverse type amplifying devices is of a type separately
provided for by a subclass in this class, as for example, a
traveling wave type amplifier classified in subclass 43 and
an electron beam tube amplifying device classified in
subclasses 44+. Where different types of vacuum tubes are
involved, only one of which is provided for by a separate
subclass, classification is not in subclass 3 but in the
subclass providing for an amplifier having an amplifier
device of that type. Combinations of vacuum tube and gaseous
tube amplifiers are classified herein. Diode vacuum tube
amplifiers combined with any other type of vacuum tube
amplifier, whether provided for as a separate subclass or
not, are classified herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
150 for cascaded vacuum tube amplifiers with amplifier
devices having different characteristics (both amplifying
devices being of the same general type).
299 for transistor amplifiers including combined diverse
type semiconductors.
310 for plural cascaded stage transistor amplifiers
including transistors having different characteristics.
Subclass:
4
This subclass is indented under the class definition.
Subject matter wherein the amplifying device combines (1) a
substance having the characteristic that certain molecular,
atomic, or nuclear particles thereof are capable of
excitation to a higher energy level; (2) means to raise such
particles to the higher energy level state; (3) means for
applying an electrical signal to the amplifying device; and
(4) means for securing the amplified output therefrom,
whereby the aforementioned excited particles in undergoing a
change from the higher to a lower energy state emit radiation
which is released by the applied electrical signal, thereby
to amplify it.
SEE OR SEARCH CLASS:
250, Radiant Energy, subclass 251 for devices for producing
and propagating a unidirectional stream of neutral molecules
or atoms through a vacuum, usually at thermal velocity and
including means to excite the molecules or atoms at a
resonant frequency.
324, Electricity: Measuring and Testing, 300 for electrical
measuring and testing means involving nuclear induction,
which refers to operation on a nuclear resonant principle
similar to that employed in masers.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous circuits which may utilize a maser type
circuit.
331, Oscillators, subclass 94.1 for oscillators of the
molecular or particle resonant type, e.g., maser type.
332, Modulators, appropriate subclasses for modulators of the
molecular or particle resonant type, e.g., maser type.
333, Wave Transmission Lines and Networks, subclass 24 for
gyrator type wave transmission coupling means, including
devices operating on a molecular or nuclear resonant
principle similar to that employed in masers.
359, Optics: Systems (Including Communication) and Elements,
333 for optical or quasi-optical maser-type amplifying
devices.
Subclass:
4.5
This subclass is indented under the class definition.
Subject matter including (1) a nonlinear reactance, (2) means
for applying an input signal frequency to said nonlinear
reactance, (3) means for effectively applying a pumping
frequency higher than said signal frequency to said nonlinear
reactance, and (4) means for abstracting the amplified output
therefrom, whereby sum and difference frequencies are
produced, one or both of which (but usually the difference
frequency {called the idler frequency} reacting with the
pumping frequency to produce energy at the signal frequency
which is combined in phase with the input signal.
(1) Note. While the pumping frequency is higher than the
signal frequency, the pumping frequency may be derived from a
lower frequency source, for example, as a harmonic of the
lower frequency source.
SEE OR SEARCH THIS CLASS, SUBCLASS:
7 for an amplifier with a capacitive amplifying device.
8 for an amplifier with a saturable reactor type amplifying
device.
53 for an amplifier with a distributed parameter coupling
means.
Subclass:
4.6
This subclass is indented under subclass 4.5. Subject matter
including structure for propagating energy of the various
frequencies in interacting relationship with the nonlinear
reactance.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for maser type amplifying devices.
5 for solid element wave propagating devices generally.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnections Systems,
subclass 424 for nonoptical parametric amplifier frequency
converters, per se.
332, Modulators, 117 or 144+ for capacitive frequency or
phase modulators, respectively, and subclass 173 for magnetic
amplitude modulators.
333, Wave, Transmission Lines and Networks, 138, for delay
networks.
359, Optics: Systems (Including Communication) and Elements,
326 for parametric optical frequency translators.
455, Telecommunications, 313 for receivers with frequency
modification or conversion which may use parametric-type
means; and subclass 336 for superrangenerative receivers.
Subclass:
4.7
This subclass is indented under subclass 4.6. Subject matter
wherein the propagating structure is an electron beam
device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
43 for travelling wave amplifiers.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems, 3.5 and
39.3, for miscellaneous travelling wave tube systems.
Subclass:
4.8
This subclass is indented under subclass 4.5. Subject matter
wherein the nonlinear reactance is of the gyromagnetic type.
(1) Note. The term "gyromagnetic" as applied to material
designates magnetically polarized material (e.g., ferrites,
garnets, and ionized gases) having unpaired spin systems
which exhibit significant precessional motion in an
orthogonal R.F. field.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4.6 for travelling wave type amplifiers involving
gyromagnetic nonlinear reactance.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 1.1 and
24.1+, for gyromagnetic plural channel systems and coupling
networks respectively.
Subclass:
4.9
This subclass is indented under subclass 4.5. Subject matter
wherein the nonlinear reactance is of the semiconductor type
(e.g., a diode).
SEE OR SEARCH THIS CLASS, SUBCLASS:
4.6 for travelling wave type parametric amplifiers whose
nonlinear reactance is of the semiconductor type.
250 for semiconductor amplifiers generally.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous nonlinear circuits.
Subclass:
5
This subclass is indented under the class definition.
Subject matter wherein the amplifying device comprises a
solid-state element wave propagating means having associated
means, such as a distributed parameter network, for coupling
a signal wave to be amplified to the wave propagating means.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for amplifiers having amplifying devices of the maser type
including those with solid element wave propagating means.
4.6 for travelling wave type parametric amplifiers which may
utilize solid-state wave propagating means.
43 for traveling wave tube amplifiers.
45 for amplifiers having amplifier devices of the electron
beam type which include an electrode coupled to a cavity
resonator.
53 for amplifiers with distributed parameter type coupling.
250 for amplifiers having amplifying devices of the
semiconductive type.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous circuits which may include subject matter
similar to the amplifiers classified in this subclass.
331, Oscillators, subclass 94.1 for oscillators of the laser
type which may include solid element wave propagating means.
332, Modulators, appropriate subclasses for modulators of the
laser type which may include solid element wave propagating
means.
333, Wave Transmission Lines and Networks, appropriate
subclasses, particularly subclass 24 for distributed
parameter transmission coupling means including coupling
means involving solid element wave propagating means.
372, Coherent Light Generators, appropriate subclasses for
laser type oscillators.
Subclass:
5.5
This subclass is indented under subclass 5. Subject matter
wherein the solid-state means is adapted to propagate and
amplify signal waves in the form of acoustic, ultrasonic or
hypersonic elastic waves of the phonon type.
SEE OR SEARCH CLASS:
181, Acoustics, subclass .5 for mechanical travelling wave
structures for propagating acoustic wave.
307, Electrical Transmission or Interconnection Systems,
subclass 424 for nonoptical parametric amplifier frequency
converters which may employ acoustic waves (e.g., Raman or
Brillcuin devices).
310, Electrical Generator or Motor Structure, 311
piezoelectric devices in general which may propagate elastic
waves of the phonon type.
333, Wave Transmission Lines and Networks, 138 for wave
delay networks and subclasses 187+ for wave filters utilizing
piezoelelectric wave propagating elements.
359, Optics: Systems (Including Communication) and Elements,
326 for parametric optical frequency translators.
367, Communications, Electrical: Acoustic Wave Systems and
Devices, for compressional wave systems or transducers which
may employ solid element wave propagating devices of the
sonic or supersonic type.
Subclass:
6
This subclass is indented under the class definition.
Subject matter wherein the amplifier includes means for
applying or varying a magnetic field, and an electrical
resistor subjected to such field or varying field in such
manner that the value of the resistance transverse to the
magnetic field changes, thus comprising a Hall Effect Device;
such Hall Effect Device may comprise the amplifying device,
per se, or may be included as a unilateralizing means
(gyrator) to insure unilateral operation of the amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
8 for amplifiers having saturable reactor amplifying
devices.
60 for amplifiers having magnetostrictive means in the
amplifying device.
62 for amplifiers having a magnetoresistive type amplifying
device.
63 for amplifiers having a magnetic means type amplifying
device not elsewhere provided for.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 511 for miscellaneous
circuits utilizing a Hall effect type element.
329, Demodulators, appropriate subclasses for demodulators
including a Hall effect element.
333, Wave Transmission Lines and Networks, subclass 24 for
Hall effect type gyrators, and subclasses 213+ for two
terminal negative resistance networks.
338, Electrical Resistors, subclass 32 for electrical
resistors whose resistance value changes in response to a
magnetic field including resistors responding in accordance
with the Hall effect.
Subclass:
7
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is a nonlinear
capacitor.
(1) Note. A nonlinear capacitor is one in which for any
frequency, the ratio of the voltage across the capacitor to
the current flowing through it, is not linear.
(2) Note. To be classified in this class the output signal
must be a substantial replica of the input signal. Subject
matter involving nonlinear capacitors in which the power
supply, which is controlled by the signal, is A.C. must
include filter means claimed to eliminate the A.C. power
supply from the output signal or classification is in Class
307, Electrical Transmission or Interconnection Systems,
subclasses 40+. However subject matter involving nonlinear
capacitor amplifying devices wherein an A.C., power supply is
used and claiming a demodulator will be classified herein
even where the output filter is not claimed, if the filter is
disclosed. It will be assumed to be part of the claimed
demodulator.
SEE OR SEARCH THIS CLASS, SUBCLASS:
8 for amplifiers having saturable reactor type amplifying
devices.
10 for amplifiers of the modulator-demodulator type.
86 for signal feedback amplifiers with variable impedance
controlled by a separate path.
95 and 110, for signal feedback amplifiers with nonlinear
impedance means.
143 for amplifiers having a thermally responsive impedance.
144 for amplifiers having a variable impedance for the
signal channel controlled by a separate control path.
164 for amplifiers having an electronic tube or diode in an
interstage coupling means.
174 for amplifiers having an electromechanical transducer
(e.g., piezoelectric crystal) in an interstage coupling
means.
183 for amplifiers having a nonlinear device in an
interstage D.C.. coupling means.
250 for amplifiers having semiconductor type amplifying
devices, particularly subclass 287.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 401
for nonlinear reactor systems.
361, Electricity: Electrical Systems and Devices, 271 and
500+ for capacitors, per se.
Subclass:
8
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is a saturable
magnetic core with at least means to apply an electrical
signal and an A.C. power supply to at least one winding
thereon; the input signal which may be D.C.. or A.C. is
applied to the signal winding to control an A.C. power supply
applied to the power winding, which may be the same winding
or a different winding.
(1) Note. To be classified in this class the signal output
of the amplifier must be a substantial replica of the input
signal. Therefore subject matter involving saturable
reactors without filter means is not classified in this class
with amplifiers, but is classified elsewhere. See the SEarch
Class: notes below. Subject matter involving saturable
reactors claiming a "demodulator" and disclosing a filter
therewith but not claiming the filter are assumed to claim
the filter as part of the demodulator and are classified
herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
7 for amplifiers having capacitive type amplifying devices
including "saturable capacitive reactor" means.
10 for modulator-demodulator type amplifiers.
60 for amplifiers having magnetostrictive means.
62 for amplifiers having magnetoresistive type amplifying
devices.
63 for amplifiers having magnetic means amplifying devices.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 416
for amplifiers using nonlinear reactors with a nonlinear
output signal.
323, Electricity: Power Supply or Regulation Systems,
subclass 249, 302, 310, and 329 for saturable inductive
reactor circuits to control voltage magnitude. See (1) Note
above.
336, Inductor Devices, 155 for the structure of saturable
inductive regulators of the static type.
361, Electricity: Electrical Systems and Devices, subclass
204 for saturable reactors with electric relay or
electromagnet load.
Subclass:
9
This subclass is indented under the class definition.
Subject matter including a periodic switching means common to
the input and output circuits of the amplifier.
(1) Note. This subclass includes essentially four types of
subject matter containing a periodic switch, as follows:
(a) Where the signal is chopped to get A.C. which is fed to
the amplifier and the amplifier output is chopped to get a
D.C.. output (this subject matter is the same as is
classified in subclass 10 below except that the modulator and
demodulator are of the chopper type).
(b) The signal to the main amplifier is not chopped but a
portion to another amplifier is combined with a signal from
the output of the first amplifier and the two are chopped to
get an A.C. signal which is used to develop a corrective
signal for the main amplifier.
(c) The input is compared to the output by a periodic switch
to develop a correction signal, generally for drift
correction.
(d) The input and output signal are combined and then
chopped and put into the main amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
83 for push-pull signal feedback amplifiers having a D.C..
feedback path.
97 for signal feedback amplifiers having a D.C.. feedback
path.
121 for push-pull amplifiers having D.C.. interstage
coupling.
125 for plural amplifiers having a D.C.. and an A.C.
channel.
159 161, 163, and 181+, for D.C.. coupling involved in the
interstage coupling.
187 and 191, for D.C.. input coupling.
194 and 198, for D.C.. output coupling.
Subclass:
10
This subclass is indented under the class definition.
Subject matter including means for modulating the signal,
which is usually D.C.. or low frequency A.C. amplifying
means, and means to restore the original signal, eliminating
any carrier frequency components.
(1) Note. The means for eliminating the carrier need not be
specifically claimed to be classified in this class if such
means are disclosed. As for example, where a demodulator is
claimed alone, and a filter means to eliminate the carrier is
disclosed the filter need not be claimed for classification
herein. The claimed demodulator will be assumed to include
the filter in such cases.
(2) Note. Where the modulator and demodulator are of the
chopper type see the search notes below.
(3) Note. Including in the "means for modulating the
signal" are chopper means to convert the signal to pulsating
direct current or alternating current.
SEE OR SEARCH THIS CLASS, SUBCLASS:
7 for amplifiers having a capacitive type amplifying device
including those which modulate and demodulate the signal.
8 for amplifiers having saturable reactor type amplifying
devices including those which modulate and demodulate the
signal.
9 for modulator and demodulator of the chopper type.
SEE OR SEARCH CLASS:
324, Electricity: Measuring and Testing, subclass 118, for
measuring systems involving modulation-demodulation.
329, Demodulators, appropriate subclasses, for demodulator
circuits.
332, Modulators, appropriate subclasses, for modulator
circuits.
Subclass:
11
This subclass is indented under the class definition.
Subject matter including means to restore a D.C.. component
to the signal, usually by means of a D.C.. bias source and a
rectifier circuit supplied to the control grid.
SEE OR SEARCH THIS CLASS, SUBCLASS:
140 for control of the input or gain control electrode
including a rectifier in the bias circuit.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 306 for miscellaneous circuits with
amplitude control means.
348, Television, 691 for television systems including D.C.
reinsertion circuits.
Subclass:
41
This subclass is indented under the class definition.
Subject matter wherein the amplifying device includes
electrodes in a gas or vapor medium and which device depends
upon ionization of a gas or vapor for its operation.
SEE OR SEARCH CLASS:
313, Electric Lamp and Discharge Devices, appropriate
subclasses, particularly subclass 161, 163, and 567+ for gas
or vapor tubes, per se.
315, Electric Lamp and Discharge Devices: Systems,
appropriate subclasses, for circuits including gas or vapor
tubes as the ultimate load device.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous electronic tube circuits including gas or vapor
tubes with a control electrode, controlled in operation.
Subclass:
42
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is a vacuum tube
including a secondary electron emissive electrode.
SEE OR SEARCH CLASS:
313, Electric Lamp and Discharge Devices, 103, 377, 379,
399+, and 532+ for vacuum tubes, per se, having secondary
emissive electrode.
315, Electric Lamp and Discharge Devices, Systems 5.11, 11,
12.1, 39.63 for circuits including vacuum tubes as load
devices having a secondary emissive electrode.
Subclass:
43
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is of the vacuum
tube type including means for generating an electron stream
or beam, and having additional means therein for propagating
an electromagnetic wave or component thereof at a velocity
reduced from the free space velocity of the wave and
propagated in proximity of the electron stream or beam,
permitting exchange of energy between the electrons and the
electromagnetic wave.
SEE OR SEARCH THIS CLASS, SUBCLASS:
5 for amplifiers having a solid element wave propagating
amplifying device.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices, Systems, 3.5 and
39.3 for traveling wave type tubes involved as the load
device in miscellaneous circuits. See the search notes under
subclasses 3.5 and 39.3.
331, Oscillators, subclass 82 for traveling wave tube type
oscillators.
Subclass:
44
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is a vacuum tube
provided with means to form the electric space discharge into
a restricted beam or ray, usually pencil-like.
(1) Note. Means to control the electron trajectory of the
electrons emitted from the cathode (as in magnetrons which
are classified below) is not regarded as an electron beam
forming means required for classification in this and
indented subclasses.
(2) Note. Subject matter broadly claiming so-called "beam
power tubes" are not classified in this subclass but are
classified below in the appropriate subclass for the circuit
involved.
SEE OR SEARCH THIS CLASS, SUBCLASS:
42 for amplifiers having secondary electron emission tube
amplifying devices.
43 for amplifiers having traveling wave type amplifying
devices.
47 for magnetrons.
308 for amplifiers including an electron beam forming means
and a semiconductor element as a target means therein.
SEE OR SEARCH CLASS:
313, Electric Lamp and Discharge Devices, 364 for
cathode-ray tubes, per se. See the search notes of Class
313.
315, Electric Lamp and Discharge Devices: Systems, 1 for
cathode- ray tubes with means to supply electric current or
potential thereto and/or cathode ray tubes structurally
combined with a circuit element. See the search notes of
Class 315.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 600 for miscellaneous
circuits having a particular beam tube structure.
329, Demodulators, appropriate subclasses and particularly
subclass 368 for an amplitude demodulator employing an
electron discharge device of three or more electrodes.
Subclass:
45
This subclass is indented under subclass 44. Subject matter
wherein at least one electrode is coupled to a cavity
resonator.
SEE OR SEARCH THIS CLASS, SUBCLASS:
49 for amplifiers having vacuum tube amplifying devices with
distributed parameter characteristics.
56 for amplifiers with cavity resonator coupling means
generally.
SEE OR SEARCH CLASS:
331, Oscillators, subclass 83 for multicavity beam tube
(Klystron) oscillators.
Subclass:
46
This subclass is indented under subclass 44. Subject matter
including means to deflect the electron beam.
SEE OR SEARCH THIS CLASS, SUBCLASS:
41 for amplifiers having gas or vapor tube amplifying
devices including those having means to deflect the ionized
gas or vapor stream.
65 for amplifiers including vacuum tube amplifying devices
having distinctive structural characteristics or specific
structural details not elsewhere provided for in the
schedule.
SEE OR SEARCH CLASS:
313, Electric Lamp and Discharge Devices, 421 for
cathode-ray tubes, per se, having electron stream or beam
deflecting means.
315, Electric Lamp and Discharge Devices: Systems, 364 for
cathode- ray tubes with means for deflecting the cathode
ray.
Subclass:
47
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is of the vacuum
tube type including means for magnetically influencing the
electric discharge in the device, and not provided for
above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
41 for amplifiers having a gas or vapor type amplifying
device including those with magnetic means to deflect the
ionized stream of gas or vapor particles.
42 for amplifiers having secondary emission tube amplifying
devices including those with magnetic means.
43 for traveling wave type tube amplifiers which may include
magnetic means.
44 for electron beam tube amplifying devices which may
include magnetic means.
SEE OR SEARCH CLASS:
313, Electric Lamp and Discharge Devices, 153 for discharge
device combined with a magnetic device. See the Notes and
search notes of Class 313.
315, Electric Lamp and Discharge Devices: Systems, 39.51 for
magnetrons. See the Notes and search Notes and search Notes
of Class 315.
329, Demodulators, subclass 322 for a magnetron type
frequency modulator and subclass 354 for a magnetron type
amplitude modulator.
331, Oscillators, 86 for magnetron oscillators.
Subclass:
48
This subclass is indented under subclass 47. Subject matter
wherein the input signal is coupled to the means for
magnetically influencing the electric discharge.
Subclass:
49
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is of the vacuum
tube type and includes within the vacuum tube an electrode or
other element having distributed parameter impedance
characteristics.
(1) Note. Distributed parameter characteristics as used in
the definition above include long lines and long line
elements such as lecher lines, parallel transmission lines in
general, concentric lines, wave guides, cavity resonators,
tuned transmission lines, etc.., which possess distributed
capacitance and inductance. For the definition of such
means, see the class definition for Class 333, Wave
Transmission Lines and Networks. Inherent capacity or
inductance as for example between electrodes or of a lead
inside the tube when made use of as a lumped reactance
circuit element is classified in the appropriate subclass
involving the circuit; neutralization by feedback is
classified in subclasses 76+ below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for amplifiers having a maser type amplifying device which
may include distributed parameter impedance structure.
5 for amplifiers having a solid element wave propagating
amplifier device.
43 for amplifiers including traveling wave tubes.
45 for amplifiers of the type having an electron beam tube
amplifying device with an electrode coupled to a cavity
resonator.
53 for amplifiers with distributed parameter type coupling.
See the search notes thereunder.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems, 39 for a
vacuum tube combined with distributed parameter type
transmission means structure, with the tube as the load
device. See the notes and search notes thereunder.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 593 for miscellaneous
circuits with distributed parameters.
359, Optics: Systems (Including Communication) and Elements,
333 for laser amplifiers.
Subclass:
50
This subclass is indented under the class definition.
Subject matter including in addition to the amplifying device
of the vacuum tube type, a similar vacuum tube, with the
cathode unheated, so that the additional tube does not serve
as an active element but merely presents impedance relations
in the circuit similar to those of the amplifying device
vacuum tube, usually for neutralizing the effects of the
amplifying device interelectrode impedances.
SEE OR SEARCH THIS CLASS, SUBCLASS:
76 for amplifiers having signal feedback means to compensate
for inter-electrode impedance. See the notes and search
notes thereunder.
Subclass:
51
This subclass is indented under the class definition.
Subject matter combined with switch means, which may be of
the electromechanical or electronic tube type (vacuum, gas,
or vapor tubes), to disable or discontinue the operation of
the amplifier automatically in response to a predetermined
condition.
(1) Note. Miscellaneous gating circuits are classified in
Class 327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclasses 365+ unless significant
details of an amplifier as classified in the class definition
of this class are claimed when classification is in this
class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
65 for specific structure involved in the amplifier
including structure involving switching means.
127 for amplifiers having means to control power supply or
bias voltage.
SEE OR SEARCH CLASS:
200, Electricity: Circuit Makers and Breakers, appropriate
subclasses, for switches, per se.
307, Electrical Transmission or Interconnection Systems, 112
for electrical transmission or interconnection switching
systems.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 365 for miscellaneous gating
circuits.
361, Electricity: Electrical Systems and Devices, 1 for
electrical systems and devices with safety and protection
means including those involving disabling switching means;
subclasses 139+ for circuits for electric relays.
Subclass:
52
This subclass is indented under the class definition.
Subject matter including means for control of the amplifier
which may be for control of the bias of an amplifier device
electrode or of a variable impedance for the signal channel,
wherein the signal input includes a component of a particular
frequency not involved in the signal for signal purpose,
which is selected by a means in or associated with the
amplifier and applied to the control means or used to develop
a control voltage applied to the control means.
(1) Note. See the class definition, Lines With Other
Classes and Within This Class, for other systems utilizing
pilot frequency control.
SEE OR SEARCH THIS CLASS, SUBCLASS:
85 for signal feedback amplifiers having an amplifier in the
feedback path.
86 for signal feedback amplifiers having a variable
impedance in the feedback path controlled by a separate
control path.
96 for signal feedback amplifiers combined with control of
bias of the signal amplifier.
127 appropriate subclasses, for control of bias or power
supply, particularly subclasses 130 and 132. See the search
notes under subclass 127. See also (2) Note under subclass
130.
143 for amplifiers having a thermally responsive impedance
which may be controlled by a separate means.
144 for amplifiers having a variable impedance which may be
controlled by a separate control path.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, appropriate
subclasses for pilot current controlled transmission line
systems, generally. See the note and search notes.
370, Multiplex Communications, subclass 491 and 500 for a
multiplexing system using pilot control.
Subclass:
53
This subclass is indented under the class definition.
Subject matter wherein the signal energy is coupled to or
from the amplifying device by means including distributed
parameter wave transmission means; or circuit networks of
lumped parameters or impedances designed to simulate the
impedance characteristics of distributed parameter wave
transmission means.
(1) Note. Distributed parameter transmission means as used
in the definition above include long lines and long line
elements such as telephone and telegraph lines, lecher lines,
parallel transmission lines, in general, concentric lines,
wave guides, cavity resonators, tuned transmission lines,
etc.., which possess distributed capacitance and inductance.
For the definition of such means and "lumped parameter or
impedance" means as used above, see the class definition for
Class 333, Wave Transmission Lines and Networks. Subject
matter involving inherent capacity or inductance, as for
example, between electrodes, or of a lead inside a tube when
made use of as a lumped reactance circuit element, is
classified in the appropriate subclass involving the circuit.
Neutralization by feedback is classified in subclasses 76+
below.
(2) Note. Subject matter including distributed parameter
circuit coupling means when combined with a special type of
amplifying device is classified with the special type of
device and not in this subclass. For example, subclass 43,
for amplifiers having traveling wave type tubes, which
include distributed parameter type delay lines, or wave
guides.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for amplifiers having plural diverse type amplifying
devices.
4 for amplifiers having a maser type amplifying device.
5 for amplifiers which have solid element wave propagating
amplifying devices.
43 for amplifiers having a traveling wave type tube
amplifying device.
45 for electron beam tube amplifying devices coupled to a
cavity resonator.
49 for amplifiers having an amplifying device of the vacuum
tube type having distributed parameter characteristics.
107 for signal feedback amplifiers having phase shift means
in the loop path.
157 for amplifier interstage coupling.
185 for amplifier input coupling.
192 for amplifier output coupling.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems,
appropriate subclasses indented under subclass 3 and
subclass 39 for distributed parameter impedance devices.
333, Wave Transmission Lines and Networks, appropriate
subclasses for passive distributed impedance devices. See
the notes under the class definitions and search notes under
the pertinent subclasses of Class 333.
Subclass:
54
This subclass is indented under subclass 53. Subject matter
wherein a plurality of amplifier devices are in a system
having a single source and load, include a delay line
coupling (which may be a distributed parameter line, or an
artificial line) and wherein the inputs or outputs of such
amplifier devices are coupled to such delay line means at
phase displaced points.
(1) Note. Push-pull amplifiers including delay line
coupling, per se, are not classified in this subclass but in
subclass 55 below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
124 for plural channel amplifiers. See the notes and search
notes thereunder.
Subclass:
55
This subclass is indented under subclass 53. Subject matter
including at least one push-pull stage of amplification.
(1) Note. A push-pull stage of amplification for this class
requires a balanced input to two tubes and a balanced output
therefrom; for further details of the definition of a
push-pull stage of amplification see the class definitions of
this class, section I.
SEE OR SEARCH THIS CLASS, SUBCLASS:
118 for push-pull amplifiers generally. See the notes and
search notes thereunder.
Subclass:
56
This subclass is indented under subclass 53. Subject matter
wherein the distributed parameter wave transmission means is
of the wave guide, cavity concentric line type and is
resonant.
SEE OR SEARCH THIS CLASS, SUBCLASS:
45 for electron beam tube amplifying device coupled to a
cavity resonator.
94 and 109, for signal feedback amplifiers having frequency
responsive means in the feedback path.
302 for semiconductor amplifiers having frequency responsive
in the signal transmission path.
SEE OR SEARCH CLASS:
331, Oscillators, subclass 83 for multicavity beam tube
oscillators (Klystrons).
333, Wave Transmission Lines and Networks, 219 for
distributed parameter type resonators. See the note and
search notes to this subclass.
Subclass:
57
This subclass is indented under subclass 53. Subject matter
wherein there is included as a signal coupling means a
circuit network of lumped parameters or impedances, which is
designed to simulate the impedance characteristics of a
distributed parameter wave transmission means.
(1) Note. Distributed parameter transmission means as used
in the definition above include long lines and long line
elements such as telephone and telegraph lines, lecher lines,
parallel transmission lines, in general, concentric lines,
wave guides, cavity resonators, tuned transmission lines,
etc.., which possess distributed capacitance and inductance.
For the definition of such means and "lumped parameter or
impedance" means as used above, see the class definition for
Class 333, Wave Transmission Lines and Networks. Subject
matter involving inherent capacity or inductance, as for
example, between electrodes, or of a lead inside a tube when
made use of as a lumped reactance circuit element, is
classified in the appropriate subclass involving the circuit.
Neutralization by feedback is classified in subclasses 76+
below.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 23, for
passive type artificial line, per se; and subclasses 138+,
for delay lines.
Subclass:
58
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is provided with
a rotating dynamoelectric means; and wherein the power supply
electrical energy source which is controlled, may be
developed by conversion of mechanical energy to electrical
energy by the motion of the armature of the dynamoelectric
means, the signal current being applied to magnetic field
means of the device, so that a current is generated which
varies with the signal current supplied; or the rotating
dynamoelectric means may act as a motor with the signal
current applied to the rotating means or the field means, and
the rotary motion of the device may be utilized as a variable
resistor means to effect a control of the power supply
source.
(1) Note. Subject matter, as defined above, is classified
herein where the device is disclosed as designed to amplify a
signal. Where the system is primarily for the conversion of
electrical energy into mechanical energy or vice versa, or is
of general utility, classification is in Class 310,
Electrical Generator or Motor Structure, or Class 322,
Electricity: Single Generator Systems, as described in the,
SEARCH CLASS, below. Where the structure of a dynamoelectric
machine is claimed, alone, classification is in the
appropriate subclass of Class 310, Electrical Generator or
Motor Structure.
SEE OR SEARCH CLASS:
310, Electrical Generator or Motor Structure, 10 and
subclasses indented thereunder for the structure of
dynamoelectric machines, per se, especially indented
subclasses 139 and 151 for the structure of generators of the
rotary amplifier type.
322, Electricity: Single Generator Systems, appropriate
subclasses particularly subclass 61 for generators with
alternating current excitation and subclasses 90 and 91+ for
rotating amplifiers, especially indented subclass 92 for such
amplifiers of the crossed-field type.
Subclass:
59
This subclass is indented under the class definition.
Subject matter including means controlled by light or
activated by light which may be involved in the amplifying
device, per se, used as a control means, or which may be
included in any other part of the amplifier.
(1) Note. Subject matter wherein light controlled or
activated means is not a part of the amplifier but is
combined therewith (as for example, as a photo-electric cell
with light means therein feeding a signal current to a vacuum
tube amplifier) is not classified in this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
308 for amplifiers having atomic particle or radiant energy
impinging on a semiconductor amplifying device. See the
search notes thereunder.
SEE OR SEARCH CLASS:
250, Radiant Energy, 200, appropriate subclasses for
photocell circuits. See also the notes and search notes
under subclass 200.
Subclass:
60
This subclass is indented under the class definition.
Subject matter wherein the amplifying device includes
magnetostrictive means, that is, means for cyclically
changing the dimensions of a body of magnetic material under
the influence of a cyclically changing magnetic field in
proximity to the body of magnetic material.
SEE OR SEARCH THIS CLASS, SUBCLASS:
174 for interstage coupling including electromechanical
transducer means (e.g., piezoelectric crystals). See the
search notes thereunder.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 148 and 186+ for
electromechanical transducer delay lines and filters,
respectively. See the search notes thereunder.
336, Inductor Devices, subclass 20 for inductive devices
having magnetostrictive (deformable) cores.
Subclass:
61
This subclass is indented under the class definition.
Subject matter wherein the amplifying device, to which the
electric input signal is applied to control the power supply
source of electric energy also applied thereto, is a
resistive means, which may be liquid, solid, or of granular
construction.
(1) Note. Not included herein, are other devices having
resistive properties such as gas tubes, vacuum tubes, etc..
(2) Note. Variable resistors, although including a sensing
means and/or power supply means, as structure are classified
in Class 338, Electrical Resistors. Where such subject
matter involves a load circuit, classification is herein,
when the signal output is "substantially a replica of the
signal input"; otherwise classification is in the appropriate
subclass of Class 323, Electricity: Power Supply or
Regulation Systems.
SEE OR SEARCH THIS CLASS, SUBCLASS:
250 for amplifiers with semiconductor type amplifying
devices. See the notes and search notes thereunder.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for systems
utilizing variable resistance devices of the nonlinear
conductor type and which systems are not elsewhere
classifiable.
338, Electrical Resistors, appropriate subclasses for the
structure of resistors, per se, especially subclass 100. See
(1) Note above.
Subclass:
62
This subclass is indented under subclass 61. Subject matter
wherein the amplifying device resistive means is of a type
whose resistance value varies in response to a magnetic field
or a change in magnetic field, and includes means for
applying such magnetic field to the resistive means.
SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for amplifiers having Hall Effect type amplifying
devices.
60 for amplifiers having magnetostrictive means.
63 for amplifiers having an amplifying device with magnetic
means, generally.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 511 for miscellaneous
circuits using the Hall effect.
338, Electrical Resistors, subclass 32 for electrical
resistors whose resistance value changes in response to a
magnetic field or a change in magnetic field.
Subclass:
63
This subclass is indented under the class definition.
Subject matter wherein the amplifying device includes a
magnetic means to control the power supply energy or is
involved in the structure of the amplifying device in some
other manner and which is not provided for above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
6 for amplifiers including Hall effect type amplifying
devices.
41 for amplifiers including gaseous or vapor type amplifying
devices which may have magnetic means for deflection or other
purposes.
44 for amplifiers having electron beam tube amplifying
devices which may have magnetic means for beam deflection,
focusing or other purposes.
47 for amplifiers having magnetically influenced discharge
devices including magnetrons.
60 for amplifiers having magnetostrictive means.
62 for amplifiers having magnetoresistive type amplifying
devices.
Subclass:
64
This subclass is indented under the class definition.
Subject matter wherein the amplifying device is of the vacuum
tube type having a positively charged grid (with respect to
the cathode) immediately adjacent the cathode, which
neutralizes the negative space charge of the electrons
emitted from the cathode so that a "virtual cathode" is
produced on the side of the space charge grid on which the
anode is situated, said tube having a normally negatively
biased control grid next to the space charge grid, to which
the signal is coupled, and an anode to receive the electrons
emitted by the cathode, and which may have additional
electrodes between the control grid and the anode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
65 for amplifiers including vacuum tubes of special
structural characteristics.
199 for power or bias voltage supply for amplifiers, see the
search notes thereunder.
SEE OR SEARCH CLASS:
313, Electric Lamp and Discharge Devices, appropriate
subclasses, for discharge device structure, per se.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 524 for miscellaneous electron tube
circuits with space charge grid tubes.
329, Demodulators, subclass 368 for an amplitude demodulator
using an electron discharge device of three or more
electrodes.
Subclass:
65
This subclass is indented under the class definition.
Subject matter involving the structure of any amplifier
circuit element, such as resistors, vacuum tubes, etc.., with
the exception of the structure of transformer elements, or of
the structural relationships of such elements in the
amplifier.
(1) Note. The term structure, herein, refers to the
arrangement in space of the parts to the whole of the circuit
element or of the elements comprising the amplifier which
includes also the material of which such parts are
constructed. The term structure is distinguished from
circuit or circuit arrangement in that the latter refers to
an abstract schematic of parts identified broadly by their
function in the circuit and arranged according to the
sequence of signal current flow and not according to actual
arrangement in space, or construction.
(2) Note. Subject matter involving the structure of
transformers is not classified in this or indented subclasses
but in subclasses 171, 190, or 197 below.
(3) Note. Subject matter involving the structure of any
amplifying device or associated therewith, of the types
specifically provided for above are not classified in this or
indented subclasses but in the appropriate subclasses for
those types, above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers having distributed parameter coupling
means including the structure of such distributed parameter
means.
SEE OR SEARCH CLASS:
174, Electricity: Conductors and Insulators, for the
structure of electrical insulators and conductors.
200, Electricity: Circuit Makers and Breakers, for the
structure of switches and circuit breakers.
313, Electric Lamp and Discharge Devices, appropriate
subclasses for the structure of electric discharge devices
(vacuum tubes and gas tubes), per se.
315, Electric Lamp and Discharge Devices: Systems, 3 for
combined cathode-ray tube and circuit element structure,
subclasses 32+ for vacuum or gas tubes combined with integral
circuit structure or temperature modifying means structure
where the tube is the load device.
334, Tuners, appropriate subclasses for tuners, per se.
336, Inductor Devices, appropriate subclasses for inductor
structure.
338, Electrical Resistors, for the structure of resistors and
rheostats.
361, Electricity: Electrical Systems and Devices, 271 for
capacitor structure, subclasses 600+ for housing and mounting
assemblies with plural diverse electrical components,
subclasses 679+ for electronic systems and devices, and
subclasses 500+ for electrolytic capacitors.
439, Electrical Connectors, appropriate subclasses for the
structure of electrical connectors.
455, Telecommunications, 130 for radio receiver structure in
general; and subclass 351 for portable radio receivers.
Subclass:
66
This subclass is indented under subclass 65. Subject matter
wherein the capacitive electrode structure, inductor
structure, resistors, conductors, connectors and/or related
circuit elements form a conductive coating on a base. For
example, such as is produced by printing, spraying,
electro-deposition or similar coating method, or by the
removal of adherent conducting material from an insulating
base by etching, grinding, or the like.
SEE OR SEARCH CLASS:
174, Electricity: conductors and Insulators, 250 for
preformed panel circuit arrangement (e.g., printed
circuits).
336, Inductor Devices, subclass 200 for inductor coil
structure of the printed circuit type. See the search notes
thereunder.
361, Electricity: Electrical Systems and Devices, 736 and
748+ for printed circuits of the type used in radios.
439, Electrical Connectors, 55 for connectors of the
preformed panel circuit (e.g., printed circuit) type.
Subclass:
67
This subclass is indented under subclass 65. Subject matter
wherein the structure involved is that of a capacitor or
capacitive element of the amplifier circuit.
SEE OR SEARCH THIS CLASS, SUBCLASS:
157 appropriate subclasses thereunder for interstage
coupling circuits involving capacitors.
185 appropriate subclasses for input coupling circuits
involving capacitors.
192 appropriate subclasses for output coupling circuits
involving capacitors.
SEE OR SEARCH CLASS:
334, Tuners, appropriate subclasses for tuned networks for
use in wave energy apparatus and comprising inductance and
capacitance elements in circuit arrangement to form a
resonant circuit and in which structure is provided for
adjusting one or both of these elements for changing the mean
resonant frequency of the circuit.
361, Electricity: Electrical Systems and Devices, 271 and
503+ for capacitor structure, per se.
Subclass:
68
This subclass is indented under subclass 65. Subject matter
wherein the structure is some means for shielding at least
part of the amplifier from external electric or magnetic
fields, or such structure to protect parts of the device from
undesired electric or magnetic fields originating in another
part of the device, or such structure to prevent the
amplifier or a part thereof from emanating undesired electric
or magnetic fields.
SEE OR SEARCH THIS CLASS, SUBCLASS:
170 for shielding involved in interstage transformers.
190 for shielding involved in input transformers.
197 for shielding involved in output transformers.
SEE OR SEARCH CLASS:
174, Electricity: Conductors and Insulators, 32 for
miscellaneous anti-inductive structures, see particularly
subclasses 35+ for miscellaneous electrical shields and
screen structures not elsewhere classifiable. The search
notes to subclasses 32+ indicate further fields of search for
anti-inductive and shielding structures.
307, Electrical Transmission or Interconnection Systems, 89
for anti-inductive means to prevent or modify the coupling
between electrical systems, particularly subclass 91, for
"shielding means". See the search notes thereunder.
333, Wave Transmission Lines and Networks, subclass 12 for
transmission line inductive or radiation interference
reduction systems which include shielding means for the
purpose. See the search notes thereunder.
334, Tuners, subclass 85 for a tuner having shielding or
housing means.
Subclass:
69
This subclass is indented under the class definition.
Subject matter including at least two sources of signal
voltage which are combined in the amplifier so that the
signal output of the amplifier is a linear function of the
sum or difference of the signal input sources.
(1) Note. Balanced input circuits or balanced output
circuits are considered single signal sources or loads in
this class. Therefore a balanced to unbalanced amplifier is
not classified in this subclass but in subclass 116 below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
74 for series energized vacuum tube amplifiers with plural
separate signal inputs.
81 for signal feedback amplifiers having at least one
push-pull stage.
116 for amplifiers having balanced-to-unbalanced coupling.
See (1) Note above.
118 for amplifiers including a push-pull stage.
124 for amplifiers with plural amplifier channels.
147 for amplifiers having plural signal inputs. See the
notes and search notes thereunder.
252 and 295, for semiconductor amplifiers having plural
channels or plural inputs.
301 for semiconductor amplifiers having
balanced-to-unbalanced or unbalanced-to-balanced coupling.
Subclass:
70
This subclass is indented under the class definition.
Subject matter including at least two amplifying devices of
the vacuum tube type, each having at least three electrodes
including a control grid electrode, wherein at least a
portion of the anode-cathode power supply current, for one of
the amplifying devices, flows in series from the power supply
source through the space discharge path of the other
amplifying device, so that the tubes are series energized (at
least in part) from the power supply.
SEE OR SEARCH THIS CLASS, SUBCLASS:
87 for cathode impedance feedback, particularly subclass
95.
128 for control means for the anode circuit including diode
space discharge paths in such circuits.
202 for anode power supply, generally. See the search notes
thereunder.
293 and 310+, for cascaded semiconductor amplifiers series
energized for power.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 530 for miscellaneous electron tube
circuits with a particular source of power or bias voltage.
329, Demodulators, appropriate subclasses for a demodulator
with particular power supply circuitry.
Subclass:
71
This subclass is indented under subclass 70. Subject matter
wherein power supply current for one or more vacuum tube
amplifying devices is supplied through at least two separate
space discharge paths of at least two vacuum tubes.
(1) Note. Subject matter including separate and distinct
groups of pairs of vacuum tubes having separate and distinct
series energized space discharge paths is also included in
this subclass.
(2) Note. A series of three or more vacuum tubes arranged
in series for power supply which comprises a single discharge
path for the anode power supply is excluded from this
subclass.
Subclass:
72
This subclass is indented under subclass 71. Subject matter
including two pairs of series energized tubes wherein one
tube of each pair is supplied through its space discharge
path with anode-cathode power supply current from the power
supply source, and wherein each of the four vacuum tubes is
arranged in the arms of a Wheatstone bridge.
Subclass:
73
This subclass is indented under subclass 70. Subject matter
including at least two separate signal output circuits.
SEE OR SEARCH THIS CLASS, SUBCLASS:
148 for signal amplifiers having plural separate signal
outputs. See the notes and search notes thereunder.
Subclass:
74
This subclass is indented under subclass 70. Subject matter
including at least two separate input circuits for each of
two series energized vacuum tube amplifying devices.
(1) Note. A balanced (or push-pull) input circuit is
treated as a single input circuit in this class and not as
two separate input circuits.
SEE OR SEARCH THIS CLASS, SUBCLASS:
69 for sum and difference amplifiers.
147 for amplifiers with plural signal inputs. See the notes
and search notes thereunder.
Subclass:
75
This subclass is indented under the class definition.
Subject matter wherein signal feedback circuit means are
provided to superimpose a portion of the electrical signal
output energy on the amplifier input signal.
(1) Note. The above amplifier may be any stage or group of
stages of a cascaded amplifier.
(2) Note. The signal feedback of amplifiers classified in
this and indented subclasses is distinguished from the type
of feedback which may be found in amplifier gain control
circuits principally in subclasses 129+ in that the latter
involves the development from the signal, of a D.C.. voltage
which is filtered and smoothed and then applied to an
amplifier electrode to control the bias thereon; whereas in
this and indented subclasses the feedback voltage which is
applied to the input electrode varies in each instant in the
same manner that the signal varies and may be in any phase
relationship with the input signal (i.e., in phase, 180 deg.
out of phase or any other phase angle relationship).
(3) Note. The term "loop path" as used in some of the
indented subclasses refers to the loop formed by the forward
signal path from the signal input electrode in the circuit to
which the signal feedback is applied to the output and in
addition the signal feedback path from the signal output
electrode from which the feedback is derived to the signal
input electrode to which the signal feedback is applied.
(4) Note. In feedback amplifiers there is an impedance
shared by the input and output circuits which may be a
transformer.
SEE OR SEARCH THIS CLASS, SUBCLASS:
291 for semiconductor amplifiers having signal feedback.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 590 for miscellaneous
circuits with signal feedback.
329, Demodulators, subclass 319 for feedback used in
frequency demodulation noise reduction, and subclass 367 for
regenerative feedback in an amplitude demodulator.
331, Oscillators, appropriate subclasses, for oscillator
circuits utilizing feedback.
700, Data Processing: Generic Control Systems or Specific
Applications, appropriate subclasses for data processing
control systems, particularly subclasses 1-89 for closed
loop feedback systems.
Subclass:
76
This subclass is indented under subclass 75. Subject matter
wherein the "signal feedback circuit means" are provided from
compensating for or nullifying the undesirable feedback
caused by any inter-electrode impedances of a vacuum tube
amplifying device.
(1) Note. The undesirable feedback effects are usually
caused by capacitive inter-electrode impedance although the
inter-electrode impedance involved may be inductive or
conductive (e.g., resistive).
(2) Note. Neutralization of the effects of inter-electrode
impedances by other than feedback means is not specifically
provided for in this and indented subclasses but is
classified with the specific circuit means involved, as for
example, in input or output coupling, (subclasses 185+ and
192+, respectively). Where the inter-electrode impedance is
made use of, as for example, where the input (grid-cathode)
capacitance is part of the tuned input circuit classification
is in the appropriate subclass considering the
inter-electrode capacitance as though it were a conventional
external circuit element.
(3) Note. Grounded grid amplifiers which inherently
mitigate the effects of inter-electrode capacitances in
vacuum tubes are classified in the cathode coupled subclasses
for which see subclasses 186 and 193 and the search notes
thereunder.
SEE OR SEARCH THIS CLASS, SUBCLASS:
50 for amplifiers having a dummy tube.
65 for the structure of elements of the amplifier circuit
including vacuum tubes but excluding transformers, per se.
292 for semiconductor amplifiers involving compensating
feedback for inter-electrode impedance (e.g.,
neutralization).
SEE OR SEARCH CLASS:
329, Demodulators, subclass 319 for feedback used in
frequency demodulation noise reduction, and subclass 367 for
regenerative feedback in an amplitude demodulator.
331, Oscillators, 175 for oscillator systems wherein the
inter-electrode impedance of the active element of the
oscillator may be compensated for stabilizing the frequency
of the generated oscillations.
Subclass:
77
This subclass is indented under subclass 76. Subject matter
including at least one push-pull stage of signal
amplification.
(1) Note. For the definition of a push-pull stage of
amplification see the class definitions, section I.
SEE OR SEARCH THIS CLASS, SUBCLASS:
81 for feedback amplifiers having at least one push-pull
stage. See the search notes thereunder.
118 for amplifiers including a push-pull stage. See search
notes thereunder. See also (1) Note above.
Subclass:
78
This subclass is indented under subclass 76. Subject matter
wherein the feedback for nullifying or mitigating the effects
of inter-electrode impedance is applied to or from an
electrode common to the input and output circuits of an
amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
87 for cathode impedance feedback. (See the search notes
thereunder).
111 for signal feedback to or from an auxiliary grid or to
the anode. See the search notes thereunder.
Subclass:
79
This subclass is indented under subclass 76. Subject matter
wherein the signal feedback for compensating for
inter-electrode impedance is coupled back to the input from
the output by means of a transformer.
SEE OR SEARCH THIS CLASS, SUBCLASS:
165 for amplifiers having interstage transformer coupling.
See the search notes thereunder.
188 for amplifier input transformer coupled circuits. See
search notes thereunder.
195 for amplifier output transformer coupled networks. See
search notes thereunder.
Subclass:
80
This subclass is indented under subclass 76. Subject matter
wherein an inter-electrode capacitance which may be between
the grid and cathode or anode and grid is compensated for by
a feedback circuit including an inductance in parallel with
such inter-electrode capacitance (in the feedback path) and
resonant therewith.
SEE OR SEARCH THIS CLASS, SUBCLASS:
109 for amplifiers having frequency responsive feedback
means.
Subclass:
81
This subclass is indented under subclass 75. Subject matter
including at least one stage of push-pull signal
amplification.
(1) Note. For the definition of a stage of push-pull
amplification see the class definition, Glossary.
SEE OR SEARCH THIS CLASS, SUBCLASS:
77 for amplifiers having at least one push-pull stage and
including feedback means to compensate for inter-electrode
impedances.
118 for amplifiers having at least one push-pull stage. See
the search notes thereunder. See also (1) Note above.
Subclass:
82
This subclass is indented under subclass 81. Subject matter
including at least one signal feedback means wherein the
signal feedback at the amplifier device input means has a
component in phase with the input signal at this point in the
circuit, and at least one signal feedback means wherein the
signal feedback at the amplifier device input means has a
component opposite in phase with the input signal at the
amplifier input to which such feedback is applied.
SEE OR SEARCH THIS CLASS, SUBCLASS:
89 for cathode-cathode feedback for cascaded adjacent
amplifier stages.
93 for combined diverse type feedback coupling including
positive feedback.
101 for positive and negative in the same path at different
frequencies.
104 for positive and negative feedback generally.
Subclass:
83
This subclass is indented under subclass 81. Subject matter
wherein the signal feedback path from the output electrode of
the amplifier device from which the signal feedback is
derived to the input electrode of the amplifying device to
which the signal feedback is applied has a D.C.. conductive
path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching input-output
comparison including those with D.C.. conductive feedback
paths.
97 for amplifiers having a D.C.. conductive signal feedback
path.
Subclass:
84
This subclass is indented under subclass 75. Subject matter
involving plural amplifier channels combined in addition, for
one or more channels, with signal feedback means above.
(1) Note. Subject matter wherein the signal feedback is
derived from the signal output of one amplifier signal
channel and applied to the signal input of another amplifier
signal channel, is classified in this subclass.
(2) Note. For the definition of plural amplifier channels
see subclass 124 below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
124 for amplifiers with plural amplifier channels. See the
notes and search notes thereunder.
Subclass:
85
This subclass is indented under subclass 75. Subject matter
wherein the "signal feedback circuit means" has an amplifier
therein, as defined in the class definition, which may have
bias control means.
SEE OR SEARCH THIS CLASS, SUBCLASS:
86 for amplifiers having a variable impedance in a signal
feedback path varied by a separate control path.
96 for amplifiers having signal feedback combined with means
to control the bias of an electrode in the signal amplifier.
129 for amplifiers having control of the input electrode or
gain control electrode bias. See the search notes
thereunder.
144 for amplifiers having a variable impedance for the
signal channel controlled by a separate control path. See the
search notes thereunder.
SEE OR SEARCH CLASS:
329, Demodulators, subclass 319 for feedback used in
frequency demodulation noise reduction, and subclass 367 for
regenerative feedback in an amplitude demodulator.
Subclass:
86
This subclass is indented under subclass 75. Subject matter
wherein the "signal feedback circuit means" has a variable
impedance therein, which is varied by means of a control
which may be a variable control voltage or a motor control
means, the control to vary the variable impedance being
derived, developed and applied by a path separate from that
involving the variable impedance and the immediately
associated signal transmission path.
(1) Note. This subclass excludes "nonlinear" or other
impedances in the signal feedback path which vary merely by
the signal feedback current flow therethrough and which are
not provided with a "separate" means to control the variable
impedance. Such subject matter is classified in subclasses
95 and 110 of this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
143 for amplifiers having a thermally responsive impedance
which may be separately controlled.
144 for amplifiers having a variable impedance for the
signal channel varied by a separate control path. See the
search notes thereunder.
Subclass:
87
This subclass is indented under subclass 75. Subject matter
wherein the "signal feedback circuit means" or the "shared
impedance of the input and output circuits" or a portion
thereof is an impedance between the cathode of a vacuum tube
amplifying device and ground or other convenient electrical
potential reference plane.
(1) Note. For this and indented subclasses the anode
current flowing through the "cathode impedance" develops a
variable signal potential on the cathode which, relative to
the grid of the same amplifying device is effective as a
negative signal feedback in that amplifying device; and which
may in addition be applied as a signal feedback from such
cathode impedance to another input electrode of the same
amplifying device (or an amplifying device of a preceding
stage); or to which cathode impedance a signal feedback may
be applied from an output electrode of the same amplifying
stage or a following signal amplifying stage.
(2) Note. Subject matter involving cathode coupling, such
as cathode follower output circuits or where coupling is to
the cathode and there is normally no cathode impedance signal
feedback as in "bootstrap" coupling (subclass 156, below) or
where no signal feedback function is indicated, is not
classified in this and indented subclasses but in the
appropriate cathode coupling subclasses below such as
subclasses 186+, for input circuit network coupling to the
cathode and subclasses 193+, for output circuit coupling from
the cathode. See the internal search notes under these
subclasses for other subclasses of this class involving
cathode coupling.
(3) Note. The above requirement of (2) Note, for
classification in this and indented subclasses, namely, that
where cathode coupling is involved an indication that signal
feedback is present in the circuit, applies to all of these
subclasses except subclass 89 involving cathode impedance
feedback between adjacent stages. Where there is
cathode-to-cathode coupling of adjacent cascaded stages
classification is in subclass 89 regardless of whether signal
feedback is indicated or not.
(4) Note. Subject matter involving a cathode impedance
which does not develop a signal feedback voltage but is
by-passed in such manner that a D.C.. bias voltage is
developed, or due to operating conditions, is disclosed, in
the case of a single by-passed resistor, as developing a
D.C.. bias there across and not a voltage varying with the
signal, are not classified in this and indented subclasses
but in subclass 142 below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for vacuum tube amplifying device amplifiers series
energized for power.
78 for signal feedback circuits compensating for
inter-electrode impedances to or from a common electrode.
119 for push-pull amplifiers involving cathode coupling.
158 for interstage coupling to the cathode.
168 for transformer interstage coupling from the cathode.
172 for interstage coupling from the cathode.
186 for input coupling to the cathode.
193 for output coupling from the cathode.
291 for semiconductor amplifiers having signal feedback
means.
297 for semiconductor amplifiers series energized for
power.
Subclass:
88
This subclass is indented under subclass 87. Subject matter
involving at least two stages of amplification wherein the
output of each stage is coupled to the input of the preceding
stage except the first, and wherein at least two of the
stages are arranged as defined in subclass 87 with signal
feedback from the cathode impedance of the latter of the
cascaded stages to the cathode impedance of a preceding
stage.
SEE OR SEARCH THIS CLASS, SUBCLASS:
92 for signal feedback to the cathode impedance of a prior
stage combined with diverse type signal feedback.
98 for signal feedback in cascaded amplifiers generally.
Subclass:
89
This subclass is indented under subclass 88. Subject matter
wherein the cathode-cathode feedback is between adjacent
stages.
(1) Note. Where there is cathode-to-cathode coupling of
adjacent cascaded stages classification is in subclass 89
regardless of whether signal feedback is indicated or not.
Subclass:
90
This subclass is indented under subclass 87. Subject matter
combined with a type of signal feedback as defined in
subclass 75, which is diverse from the type of feedback
defined in subclass 87.
Subclass:
91
This subclass is indented under subclass 90. Subject matter
wherein the diverse signal feedback is derived from the
cathode feedback impedance and fed to the input electrode of
the same or a prior stage; or wherein the diverse signal
feedback is derived from an output electrode of the same or a
following stage and applied to the cathode impedance.
SEE OR SEARCH THIS CLASS, SUBCLASS:
78 for signal feedback to or from a common electrode
compensating for inter-electrode impedance.
Subclass:
92
This subclass is indented under subclass 91. Subject matter
wherein the diverse signal feedback is derived from an
electrode other than the cathode and applied to the cathode
impedance of a prior stage whereby the diverse signal
feedback path includes or overlaps the cathode impedance
feedback path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
100 for amplifiers having multiple signal feedback paths in
general, including signal feedback to the input of a prior
stage.
Subclass:
93
This subclass is indented under subclass 90. Subject matter
including a signal feedback means whereby the feedback has a
component in phase with the signal applied at the input
electrode to which the signal feedback is applied.
SEE OR SEARCH THIS CLASS, SUBCLASS:
82 for push-pull amplifiers having positive and negative
feedback.
89 for cathode-to-cathode feedback between adjacent stages.
101 for positive and negative feedbacks in the same path at
different frequencies.
104 for positive and negative feedback, generally.
112 for positive feedback, generally.
SEE OR SEARCH CLASS:
329, Demodulators, subclass 367 for an amplitude demodulator
utilizing regenerative feedback.
331, Oscillators, appropriate subclasses for oscillators
operating on the positive feedback principle.
333, Wave Transmission Lines and Networks, 213 for negative
resistance and/or reactance networks of the active element
type which usually include positive feedback.
455, Telecommunications, subclass 336 for superregenerative
receivers; and subclass 337 for regenerative receivers.
Subclass:
94
This subclass is indented under subclass 87. Subject matter
including in the "cathode impedance to ground signal feedback
path" or in shunt therewith circuit means which acts on the
signal feedback to affect some frequency component of the
signal feedback differently from the other frequency
components of the signal feedback, for example, a tuned
circuit or filter circuit which eliminates a frequency
component, or an equalizer which emphasizes or de-emphasizes
the signal feedback amplitude of some frequency or frequency
range of the signal feedback with respect to others.
SEE OR SEARCH THIS CLASS, SUBCLASS:
107 for amplifiers having phase shift means in the loop
path.
109 for amplifiers having frequency responsive signal
feedback means.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24 for passive
coupling networks in general.
Subclass:
95
This subclass is indented under subclass 87. Subject matter
wherein the "cathode impedance signal feedback path" has
therein a nonlinear impedance circuit element, which may be
resistive, capacitive, or inductive, and whose impedance is
such, that the relationship for changes in voltage, between
the voltage across the nonlinear element to the current flow
therein is nonlinear.
SEE OR SEARCH THIS CLASS, SUBCLASS:
86 for amplifiers having a variable impedance in the
feedback path varied by a separate control path. See the
search notes thereunder.
110 for amplifiers having a nonlinear impedance device in
the loop path.
183 for amplifiers having a D.C.. interstage coupling means
including a nonlinear impedance element. See the search
notes thereunder.
Subclass:
96
This subclass is indented under subclass 75. Subject matter
combined with bias voltage control means for a signal
amplifying device.
(1) Note. For the definition of an amplifier with bias
voltage control see subclass 129 below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
129 for amplifiers having bias voltage control means. See
the search notes thereunder.
Subclass:
97
This subclass is indented under subclass 75. Subject matter
wherein the signal feedback path, from the output electrode
of the amplifying device from which the signal feedback is
derived to the input electrode of the amplifying device to
which the signal feedback is applied, is a D.C.. conductive
path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching means for
input-output comparison including those with D.C.. conductive
feedback paths.
83 for push-pull amplifiers having D.C.. conductive signal
feedback paths.
Subclass:
98
This subclass is indented under subclass 75. Subject matter
including at least two stages of amplification (each as
defined in the class definition) wherein the means for
coupling the input signal for each stage except the first is
coupled to the means for coupling the output signal of the
preceding amplifier; combined with signal feedback means
above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
88 for cathode-cathode signal feedback in cascaded
amplifiers.
92 for cascaded amplifiers with signal feedback to the
cathode impedance of a prior stage.
Subclass:
99
This subclass is indented under subclass 98. Subject matter
including at least two signal feedback circuit means as
defined therein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
88 for cascaded amplifiers having cathode-to-cathode signal
feedback.
90 for amplifiers having cathode impedance signal feedback
combined with diverse type signal feedback coupling.
Subclass:
100
This subclass is indented under subclass 99. Subject matter
wherein at least one of the signal feedback means has the
signal feedback applied to the signal input of a prior stage
so that the path of such feedback means extends to include
all or a portion of at least one other signal feedback means
(overlapping feedbacks).
SEE OR SEARCH THIS CLASS, SUBCLASS:
88 for cascaded amplifiers having cathode-to-cathode signal
feedback means.
92 for cascaded amplifiers including feedback to the cathode
impedance of a prior stage.
Subclass:
101
This subclass is indented under subclass 75. Subject matter
wherein a single signal feedback circuit means through an
impedance shared by the same input and output circuits has
for currents flowing through the same shared feedback
impedance at one frequency a signal feedback in phase
(positive feedback) with the signal input where the signal
feedback is applied and at least at some other frequency a
signal feedback component flowing through the same feedback
impedance, in opposite phase with the signal (negative
feedback).
SEE OR SEARCH THIS CLASS, SUBCLASS:
82 for amplifiers having at least one stage of push-pull
amplification including both positive and negative feedback.
89 for cascaded amplifiers having cathode-cathode signal
feedback between adjacent stages.
93 for amplifiers having cathode impedance feedback and
positive feedback.
104 for amplifiers having multiple signal feedbacks
including both positive and negative feedback.
Subclass:
102
This subclass is indented under subclass 75. Subject matter
including signal feedback proportional to the current flow
through the output load which receives the amplified signal,
and signal feedback proportional to the voltage across the
output load.
SEE OR SEARCH THIS CLASS, SUBCLASS:
105 for amplifiers with signal feedback from an impedance in
series with the output load (e.g., current feedback).
Subclass:
103
This subclass is indented under subclass 75. Subject matter
including two or more signal feedback circuit means as
therein defined and not previously provided for in this
schedule.
SEE OR SEARCH THIS CLASS, SUBCLASS:
88 for cascaded amplifiers having cathode-cathode signal
feedback.
90 for cathode impedance signal feedback combined with
diverse type signal feedback.
99 for cascaded amplifiers having multiple feedbacks.
102 for amplifiers having current and voltage feedback.
Subclass:
104
This subclass is indented under subclass 103. Subject matter
including at least one signal feedback means having a
component of the signal feedback in phase with the signal at
the point in the circuit where the signal is applied and at
least one signal feedback circuit means having a signal
feedback component which is in phase opposition with the
signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
82 for push-pull amplifiers having negative and positive
feedback means.
89 for cascaded amplifiers having cathode-cathode signal
feedback between adjacent stages.
93 for cathode impedance feedback combined with diverse type
feedback coupling including positive feedback.
101 for positive and negative feedback in the same path at
different frequencies.
SEE OR SEARCH CLASS:
329, Demodulators, subclass 367 for an amplitude demodulator
utilizing regenerative feedback.
331, Oscillators, appropriate subclasses for oscillators
operating on the positive feedback principle.
333, Wave Transmission Lines and Networks, 213 for negative
resistance and/or reactance networks of the active element
type which usually include positive feedback.
455, Telecommunications, subclass 336 for superregenerative
receivers; and subclass 337 for regenerative receivers.
Subclass:
105
This subclass is indented under subclass 75. Subject matter
wherein the signal feedback is from an impedance in series
with the output load which receives the amplified signal,
whereby the signal feedback voltage is proportional to the
current flowing in the output load.
SEE OR SEARCH THIS CLASS, SUBCLASS:
102 for amplifiers having current and voltage feedback.
Subclass:
106
This subclass is indented under subclass 75. Subject matter
wherein the "signal feedback circuit means" is in series with
the signal input source between the point in the signal
circuit from which the signal feedback is derived to the
point in the circuit at which the signal feedback is
applied.
Subclass:
107
This subclass is indented under subclass 75. Subject matter
wherein the "loop path" (see (3) Note under subclass 75 for
the definition of loop path) includes voltage or current
phase shift or delay means which may shift the phase of the
voltage or current of one signal frequency or signal
frequency feedback component with respect to another or shift
the phase of the voltage of the signal or signal feedback
with respect to the current.
(1) Note. Transformer or amplifier means which inherently
shift the phase 1805 are not regarded as phase shift or
voltage delay means for this subclass. If such transformer or
amplifier include additional phase shift means classification
is herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers having distributed parameter coupling
which may include electric wave delay means.
101 for amplifiers having positive and negative feedback in
the same path at different frequencies.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
subclasses 212-219 for phase control systems in general.
333, Wave Transmission Lines and Networks, 138 for electric
wave delay networks, of the passive type, see the search
notes thereunder.
Subclass:
108
This subclass is indented under subclass 75. Subject matter
wherein the signal transmission path and the "signal feedback
circuit means" both include a potentiometer or a part thereof
in common.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems, for
voltage magnitude control systems in general, including
resistors.
Subclass:
109
This subclass is indented under subclass 75. Subject matter
wherein the "signal feedback circuit means" includes circuit
means which acts on the signal feedback to affect some
frequency component of the signal feedback differently from
the other frequency components of the signal, as for example,
a tuned circuit which eliminates a frequency component of the
signal feedback or an equalizer which emphasizes or
de-emphasizes the amplitude of some frequency range of the
signal feedback with respect to others.
SEE OR SEARCH THIS CLASS, SUBCLASS:
94 for frequency responsive cathode impedance feedback
means.
107 for signal feedback amplifiers including phase shift
means in the loop path including those involving frequency
responsive feedback means.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 28 and
167+ for frequency responsive passive coupling networks in
general. See the search notes thereunder.
Subclass:
110
This subclass is indented under subclass 75. Subject matter
wherein the "loop path" (see (3) Note under subclass 75 for
the definition of loop path) includes a nonlinear impedance
circuit element, which may be resistive, capacitive, or
inductive, and whose impedance is such for changes in voltage
applied thereto that the relationship between the voltage
across such element to the current flow through the element
is nonlinear.
SEE OR SEARCH THIS CLASS, SUBCLASS:
86 for amplifiers having a variable impedance in the
feedback path varied by a separate control path. See the
search notes thereunder.
95 for amplifiers having a nonlinear impedance element in
the cathode impedance feedback path.
143 for amplifiers having a thermally responsive impedance
in the signal path.
183 for amplifiers having a D.C.. interstage coupling means
including a nonlinear impedance element. See the search
notes thereunder.
Subclass:
111
This subclass is indented under subclass 75. Subject matter
wherein the amplifying device or devices involved are of the
vacuum tube type and wherein the signal feedback is derived
from an electrode thereof other than the anode or cathode
and/or is applied to an electrode thereof other than the
cathode or control grid.
SEE OR SEARCH THIS CLASS, SUBCLASS:
160 for interstage signal coupling involving coupling to the
screen grid, plate, suppressor grid (and grid other than the
control grid or cathode). See search notes thereunder.
162 for interstage signal coupling from a grid (from an
electrode other than anode or cathode). See search notes
thereunder.
Subclass:
112
This subclass is indented under subclass 75. Subject matter
wherein the signal feedback has a component in phase with the
signal where the feedback is applied and which is not
provided for above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
82 for push-pull amplifiers including positive signal
feedback.
89 for cascaded amplifiers having cathode-cathode signal
feedback.
93 for cathode impedance signal feedback combined with
diverse type signal feedback including positive signal
feedback.
101 for positive and negative feedback in the same path at
different frequencies.
104 for positive and negative feedbacks combined,
generally.
SEE OR SEARCH CLASS:
331, Oscillators, appropriate subclasses for oscillators
operating on the positive feedback principle.
333, Wave Transmission Lines and Networks, 213 for negative
resistance and/or reactance networks of the active element
type which usually include positive feedback.
455, Telecommunications, subclass 336 for superregenerative
receivers; and subclass 337 for regenerative receivers.
Subclass:
113
This subclass is indented under the class definition.
Subject matter including a polyphase power supply for the
energizing or bias voltage supply applied to any electrode or
for a filament or for any heater for a cathode electrode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
114 for amplifiers having unrectified power supply.
199 for amplifiers involving power or bias voltage supply.
See the search notes thereunder.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 13
for plural load systems of the polyphase type.
310, Electrical Generator or Motor Structure, appropriate
subclasses under 10 for dynamoelectric machine structure of
the polyphase type.
323, Electricity: Power Supply or Regulation Systems,
appropriate subclasses for systems in which a single source
of supply is connected to a single load and the system
includes means for controlling only the magnitude of the
current, the voltage, and/or the phase angle between the
current and the voltage in the system. The single source may
be a polyphase source.
336, Inductor Devices, 5 for the structure of polyphase
inductor devices.
363, Electric Power Conversion Systems, particularly 148 for
phase conversion systems from one number of phases to a
different number of phases.
Subclass:
114
This subclass is indented under the class definition.
Subject matter wherein the source of electrical energy which
is controlled by the electrical signal is an A.C. electrical
source, which is applied as an A.C. power supply directly to
an electrode without any intervening rectifiers to rectify
the A.C. electrical supply.
(1) Note. Special types of amplifiers are classified above
and subject matter involving unrectified A.C. as a power
supply would be classified with the special type of amplifier
and not herein. The amplifiers having general vacuum tube
amplifying devices with this feature are classified herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for vacuum tube amplifying devices series energized.
113 for amplifiers having a polyphase power supply.
199 for amplifiers involving power or bias voltage supply
means, generally. See also search notes thereunder.
296 and 297, for semiconductor amplifiers involving bias or
power supply circuits.
SEE OR SEARCH CLASS:
363, Electric Power Conversion Systems, appropriate
subclasses thereunder, for power supply means combined with
means to convert A.C. to D.C.. or vice versa.
Subclass:
115
This subclass is indented under subclass 114. Subject matter
wherein the electrode, to which the A.C. power supply voltage
is applied, is a filamentary directly heated cathode.
(1) Note. A.C. power supply for heaters of indirectly
heated cathodes are not classified in this subclass but are
classified in subclass 113, above, in the special case where
they involve a polyphase power supply. Amplifiers with
cathode filaments heated by the anode current are classified
in subclass 201 of this class. Amplifiers with heater supply
otherwise are classified in subclass 199.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems,
appropriate subclasses indented under subclass 94,
particularly subclasses 97 and 105+ for subject matter
involving A.C. power supply to cathodes or cathode heaters.
Subclass:
116
This subclass is indented under the class definition.
Subject matter including a circuit in the signal path in the
conductors of which electrical signal flows so that at any
instant the signal potential in the conductors is
substantially equal and opposite in sign with reference to
ground or some other convenient reference potential plane;
and wherein further, in the signal path there is included a
circuit in the conductors of which signal flows which is
unbalanced to ground comprising a single-sided output load
usually of two conductors one of which is at ground or
reference potential.
(1) Note. Subject matter as defined above including
additional unbalanced output or load circuits as set forth
above is also classified in this subclass.
(2) Note. Balanced circuits are considered as single
sources or single loads in this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
69 for sum and difference amplifiers.
117 for amplifiers having unbalanced to balanced coupling.
118 for amplifiers including a push-pull stage. See the
search notes thereunder.
301 for semiconductor amplifiers having balanced to
unbalanced circuits.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 594 for miscellaneous
circuits with particular coupling or decoupling means.
329, Demodulators, appropriate subclasses for demodulators
with balanced to unbalanced coupling.
333, Wave Transmission Lines and Networks, 4 and 25+ for
balanced to unbalanced passive circuits. See the search notes
under subclasses 4 and 25.
Subclass:
117
This subclass is indented under the class definition.
Subject matter including in the signal path a circuit
electrically unbalanced to ground, or a convenient electrical
reference potential plane, from a single source of electrical
signal and having at some subsequent location of the signal
path, with or without one or more intervening amplifying
devices, a balanced circuit wherein at least two of the
conductors have at any instant electrical signal flowing
therethrough substantially equal and opposite in sign with
reference to ground or some other convenient reference
plane.
(1) Note. Balanced circuits are treated as single sources
of electrical signal or as single loads in this class.
(2) Note. Phase splitters are classified in this subclass.
Phase inverter amplifier circuits are classified in this
subclass and subclass 116 above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
116 for amplifiers having balanced-to-unbalanced coupling.
118 for amplifiers having a push-pull stage. See the notes
and search notes thereunder.
301 for semiconductor amplifiers having unbalanced to
balanced circuits.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 594 for miscellaneous
circuits with particular coupling or decoupling means.
329, Demodulators, appropriate subclasses for demodulators
with unbalanced to balanced coupling.
333, Wave Transmission Lines and Networks, 4 and 25+ for
unbalanced-to-balanced passive circuits. See the search
notes under the subclasses 4 and 25.
Subclass:
118
This subclass is indented under the class definition.
Subject matter including two amplifiers as defined in the
class definition, the input electrodes of each of the
amplifying devices of the two amplifiers being balanced to
ground or some other convenient electrical reference plane,
the source of electrical signal being such, and so coupled to
the input electrodes, that at any instant the signal on each
input electrode is substantially equal and opposite in sign
to the signal on the other input electrode; and wherein the
signal on the output electrodes of each of the amplifying
devices is similarly balanced to a convenient electrical
reference plane.
(1) Note. A balanced signal circuit is treated as a special
case of a single source or a single load, in this class.
(2) Note. A push-pull amplifier is treated as a single
channel with a single source and a single load in this
class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
55 for push-pull amplifiers including a push-pull stage.
69 for sum and difference amplifiers similar in structure to
push-pull amplifiers.
71 particularly subclass 72, for push-pull amplifiers
included in series energized vacuum tube arrangements.
77 for push-pull amplifiers having feedback compensation to
mitigate inter-electrode impedance effects.
81 for amplifiers having at least one push-pull stage having
signal feedback.
116 for amplifiers with balanced-to-unbalanced coupling.
117 for amplifiers with unbalanced-to-balanced coupling
including phase splitters.
262 for semiconductor amplifiers including a push-pull
stage.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 595 for miscellaneous
circuits including push pull circuits.
333, Wave Transmission Lines and Networks, 4 and 25+ for
passive balanced networks. See the search notes under
subclasses 4 and 25.
Subclass:
119
This subclass is indented under subclass 118. Subject matter
wherein the two amplifying devices in push-pull are vacuum
tube amplifying devices and wherein the input electrodes or
the output electrodes are the cathode electrodes of the
vacuum tube amplifying devices.
SEE OR SEARCH THIS CLASS, SUBCLASS:
158 for amplifiers with interstage coupling to the cathode
of an amplifying device.
168 and 172, for interstage coupling from the cathode.
186 for input coupling to the cathode. See the search notes
thereunder.
193 for output coupling from the cathode. See search notes
thereunder.
Subclass:
120
This subclass is indented under subclass 118. Subject matter
including at least two cascaded stages of amplification, each
stages as defined in subclass 118 above and each stage
excepting the first having its signal input coupled to the
signal output of the preceding stage involving specific
details or distinctive characteristics of the coupling
between the stages.
SEE OR SEARCH THIS CLASS, SUBCLASS:
157 for interstage coupling. See the search notes
thereunder.
Subclass:
121
This subclass is indented under subclass 120. Subject matter
wherein the signal coupling path from the output electrode of
each amplifying device of the preceding stage to the input
electrode of the corresponding device of the following stage
is a D.C.. conductive path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
159 161, 163, 172, and 181+, for various types of interstage
D.C.. coupling. See also the search notes thereunder.
Subclass:
122
This subclass is indented under subclass 118. Subject matter
involving specific details or distinctive characteristics of
the input and/or output circuits coupling the source to the
amplifying devices and the amplifying devices to a load,
respectively.
SEE OR SEARCH THIS CLASS, SUBCLASS:
185 for amplifier input networks. See the notes and search
notes thereunder.
192 for amplifier output networks. See the notes and search
notes thereunder.
Subclass:
123
This subclass is indented under subclass 118. Subject matter
including means to control the power supply and/or bias
voltage supply applied to the electrodes of the amplifying
devices; and/or subject matter under subclass 118 involving
specific details or distinctive characteristics of the power
or bias voltage supply of the amplifying devices.
SEE OR SEARCH THIS CLASS, SUBCLASS:
127 for amplifiers with control of power supply or bias
voltage. See the notes and search notes thereunder.
129 for amplifiers with control of input electrode or gain
control electrode bias. See the notes and search notes
thereunder.
199 for amplifier power or bias supply voltages. See the
notes and search notes thereunder.
Subclass:
124
This subclass is indented under the class definition.
Amplifier systems wherein there are at least two signal
channels each containing an amplifier as defined in the class
definition, (Section I).
(1) Note. For this and indented subclasses such amplifier
channels may be separate; in parallel with a common source
and a common load; or in branched circuit channels from
separate sources or to separate loads.
(2) Note. Sum and difference amplifiers involving two or
more signal inputs to the same channel or a different channel
where the output is proportionally the sum or difference of
the plural inputs are not classified herein. See the search
notes below.
(3) Note. A balanced circuit is regarded as a single source
or load for the purposes of classification in these
subclasses. A push-pull amplifier is regarded as a single
amplifier channel for purposes of classification in this
class. Balanced circuits and push-pull amplifiers are to be
found in this class.
(4) Note. The plural channels need not amplify or operate
simultaneously to be classified herein. Subject matter
involving plural channels with switching means to select with
alternatively one or more channels to amplify a signal a
classified in this or indented subclasses.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for amplifiers having diverse type amplifying devices.
53 for amplifiers having distributed parameter coupling.
55 for amplifiers having distributed parameter coupling;
69 for sum and difference amplifiers. See (2) Note above.
70 for amplifiers with series arranged amplifier devices.
71 for series energized amplifier devices;
73 for plural outputs.
74 for plural separate signal inputs.
77 for push-pull amplifiers with feedback compensation for
the effects of inter-electrode capacitance (e.g.,
neutralization);
81 for signal feedback amplifiers having at least one
push-pull stage;
84 for signal feedback amplifiers with plural amplifier
channels.
116 for amplifiers with balanced-to-unbalanced coupling;
117 for amplifiers having unbalanced-to-balanced coupling;
and subclasses
118 for amplifiers including a push-pull stage.
147 for amplifiers having plural input sources.
148 for amplifiers having plural loads.
151 for cascaded amplifiers with means to by-pass a stage.
252 and 295, for plural semiconductor amplifier channels.
262 301 for semiconductor amplifiers;
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 11
and 43+ for plural load circuit and supply circuit systems
respectively.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous nonlinear circuits utilizing electron tube or
semiconductor devices.
333, Wave Transmission Lines and Networks, 1 for plural
channel passive network systems.
381, Electrical Audio Signal Processing and Systems, subclass
77 for program distribution systems involving distribution
of a program to a plurality of local stations where the
program is amplified and reproduced.
Subclass:
125
This subclass is indented under subclass 124. Subject matter
wherein at least one of the signal channels has a D.C..
conductive path from source to load, or where branched
channels are involved, from or to the common junction point
of the channels to the separate loads or from the separate
sources or between common junction points in parallel
channels; and at least one other channel has its signal
transmission path, as set forth above, involves coupling
circuits which will conduct only A.C. signals, because of
signal coupling by a series condenser or transformer, and
which will not conduct D.C.. in that signal channel circuit.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching input-output
comparison.
10 for modulator-demodulator type amplifiers.
Subclass:
126
This subclass is indented under subclass 124. Subject matter
wherein at least one of the channels amplifies a signal of a
different frequency from at least one other channel.
SEE OR SEARCH CLASS:
381, Electrical Audio Signal Processing Systems and Devices,
111, for amplifier systems including microphones and/or loud
speakers having plural amplifier channels which pass
different frequency bands.
Subclass:
127
This subclass is indented under the class definition.
Subject matter combined with means to control the voltage of
the source of electrical energy which is supplied to the
amplifying device, or combined with means to control a bias
voltage applied to an electrode, such control means,
generally, being applied to stabilize the power supply or
bias voltage or to alter the operation of the amplifying
device in a predetermined manner as, for example, to control
the signal amplitude, or means to regulate the power, heater,
or filament supply of the amplifying device.
(1) Note. Limiters of the active element type which "clip"
the signal are not classified herein. Limiters combined with
amplifiers where the bias of an electrode of the amplifier is
controlled to "accommodate" a given maximum signal (where
there is no clipping of the signal) are classified herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching input-output
comparison.
11 for amplifiers having D.C.. reinsertion circuits.
51 for amplifiers combined with automatic disabling switch
means.
52 for amplifiers having pilot frequency control means.
59 for amplifiers having light control or activated means.
70 for series energized vacuum tube amplifiers.
85 for signal feedback amplifiers having an amplifier in the
feedback path including the control of bias of such feedback
amplifiers.
86 for signal feedback amplifiers having a separately
controlled variable impedance in the feedback path.
96 for signal feedback amplifiers having bias voltage
control of the signal amplifier.
113 for polyphase power supply.
114 for unrectified A.C. power supply for an electrode.
123 for control of bias voltage or power supply voltage in
push-pull amplifiers.
143 for amplifiers having a thermally responsive impedance.
144 for amplifiers having a variable impedance for the
signal path varied by a separate control path.
164 for cascaded amplifiers having an electronic tube or
diode in the interstage coupling.
174 for cascaded amplifiers having an electro-mechanical
transducer (e.g., piezoelectric crystal in the interstage
coupling path.
179 and 180, for cascaded amplifiers having an inductance in
the anode or grid circuit, or a resistance in the anode and
grid circuit in the capacitance-coupled interstage coupling,
respectively.
183 for cascaded amplifiers having a nonlinear device in the
D.C.. interstage coupling path.
199 for amplifiers with significant power or bias voltage
supply.
254 and 278+, for semiconductor amplifiers having signal
amplitude (volume level) control including such means where
the bias is controlled.
290 for semiconductor amplifiers having D.C.. feedback bias
control for stabilization.
297 for series energized cascaded semiconductor amplifiers.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 31
and 52+ for current or voltage control of electrical
transmission or interconnection systems.
323, Electricity: Power Supply or Regulation Systems, for
limiters of the active element type which "clip" the signal;
see appropriate subclasses for voltage magnitude control
systems generally.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 309 for amplitude limiting means.
329, Demodulators, appropriate subclasses for automatic
control of the bias of a demodulating element.
333, Wave Transmission Lines and Networks, particularly 2
for automatic control of plural channel passive networks,
subclass 14 for compressors and expanders, subclasses 15 and
16 for pilot signal controlled systems, subclasses 17.1+ for
automatically controlled lines or networks, and subclass 81
for attenuators. See also the search Notes under these
subclasses.
338, Electrical Resistors, for the structure of resistors,
rheostats, and potentiometers, per se.
455, Telecommunications, 234.1 for automatic volume control
in radio receivers; and subclass 343 for particular power or
bias supply for radio receivers.
Subclass:
128
This subclass is indented under subclass 127. Subject matter
wherein the "combined control means" is in the circuit from
the power supply or bias voltage source means to the anode or
screen grid electrode of a vacuum tube amplifying device or
in shunt therewith, in such manner, as to control the power
supply or bias voltage applied to the anode or screen grid
electrode.
(1) Note. Ordinary anode or screen grid resistors as such
are not control means such as is classified in this subclass.
However glow tubes, nonlinear resistors, diodes, vacuum
tubes, etc.., in the anode or screen grid supply circuit for
voltage regulation and related subject matter are classified
herein. Such matter involving ordinary resistors or other
nonlinear impedances in the power or bias supply circuits are
classified in the appropriate coupling subclass, when the
particular nonlinear element affects the signal coupling, and
not the power supply. Subject matter wherein such impedance
is isolated from the signal path or is involved only in the
power supply circuit or forms the means for isolating the
power supply circuit and is not involved in signal coupling
as, for example, signal by-pass means for the power supply,
classification is in the appropriate subclass indented under
subclass 199 below.
(2) Note. Nonlinear impedances, vacuum tube impedances,
thermal impedances, etc.., in amplifier circuits as indicated
are classified in this class. See the search notes below.
SEE OR SEARCH THIS CLASS, SUBCLASS:
52 for pilot frequency control means which may utilize
thermal or other nonlinear control means.
70 for series energized vacuum tube amplifier devices having
the anode energized through the discharge path of a
controlled vacuum tube.
86 for signal feedback amplifiers having a variable
impedance in the feedback path.
95 and 110, for nonlinear impedance in the cathode impedance
feedback path and for a nonlinear impedance element in the
loop path of feedback amplifiers respectively.
96 for feedback amplifiers combined with control of bias
voltage of the signal amplifier.
123 for control of anode or screen grid voltage in push-pull
amplifiers.
131 for amplifiers having a bias control voltage applied to
an electrode separate and distinct from the signal input
electrode.
143 for a thermally responsive impedance in the amplifier
circuit (when not specifically involved in power or bias
supply circuit as in subclass 128).
144 for variable impedance for the signal channel,
controlled by a separate control path, particularly subclass
145 where the variable impedance is an electron tube or a
diode.
164 for amplifier interstage coupling including an
electronic tube or diode.
174 for amplifiers having an electromechanical transducer
(e.g., piezoelectric crystal) in an interstage coupling
circuit.
183 for amplifiers having a nonlinear device in a D.C..
interstage coupling.
254 and 278+, for semiconductor amplifiers including
nonlinear impedance elements used for signal volume level
control.
256 272 and 289, for semiconductor amplifiers including
transistor temperature control.
290 for semiconductor amplifiers having bias control D.C..
feedback stabilization which may involve nonlinear impedance
elements.
291 for semiconductor signal feedback amplifiers which may
involve nonlinear impedance elements.
296 297, for semiconductor cascaded amplifiers series
energized for power involving bias or power supply
circuitry.
299 for semiconductor amplifiers combined with a
semiconductor impedance device.
Subclass:
129
This subclass is indented under subclass 127. Subject matter
wherein the "means to control the bias voltage" is applied to
an input electrode of the amplifying device, or to an
electrode separate and distinct from the signal input
electrodes and in vacuum tube amplifiers also separate and
distinct from the anode or screen grid electrodes in order to
control the bias of such electrode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching input-output
comparison.
11 for amplifiers with D.C.. reinsertion circuits.
52 for amplifiers have pilot frequency control means.
85 for signal feedback amplifiers having an amplifier in the
feedback path including such feedback amplifiers having means
to control the bias of an input or gain control electrode,
thereof.
96 for amplifiers having signal feedback with means to
control the bias voltage on an electrode of the signal
amplifier.
123 for bias voltage control of input or gain control
electrode in push-pull amplifiers.
254 and 278+, for semiconductor amplifiers having signal
volume level control.
290 for semiconductor amplifiers having D.C.. feedback bias
control for stabilization.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
subclass 227 and 291 for discharge control devices for
voltage magnitude control including bias control means.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 309 for miscellaneous circuits
including bias voltage control means for amplitude limiting.
333, Wave Transmission Lines and Networks, subclass 14, 15
and 213+ for companders, pilot line controlled systems, and
active element negative resistors or reactors, respectively
including such subject matter with bias control means.
363, Electric Power Conversion Systems, appropriate
subclasses for electrical conversion, including control of
the line voltage.
455, Telecommunications, 234.1 for automatic volume control
in radio receivers; and subclass 343 for particular power or
bias supply for radio receivers.
Subclass:
130
This subclass is indented under subclass 129. Subject matter
wherein the "means to control the bias voltage" includes a
source of control voltage from a system outside the amplifier
system itself.
(1) Note. An example is a seismic amplifier wherein a
battery not involved in supplying amplifier power or bias
voltage charges an RC circuit which is applied to the control
grid or an input grid of the amplifier when the shot blast is
fired. Such additional means where it includes the detector
or other related means of the seismic system, per se, is not
classified herein. See the Search Class notes below..
(2) Note. Subject matter, wherein the control voltage is
derived from a special pilot frequency voltage transmitted to
the amplifier with the signal to be amplified, is not
classified herein.
(3) Note. Subject matter wherein an oscillator (exclusive
of any other source external to the amplifier) supplies the
control bias is not classified herein. Also sources of bias
voltage as such, where no cooperation from a system outside
the amplifier is involved are classified with amplifiers.
Where specific details of the external system are claimed as
in the example under (1) Note above, as qualified in the last
three lines, classification is not with amplifiers but with
the external system.
SEE OR SEARCH THIS CLASS, SUBCLASS:
51 for amplifiers combined with automatic disabling switch
means.
52 for subject matter, wherein the control voltage is
derived from a special pilot frequency voltage transmitted to
the amplifier with the signal to be amplified. See (2) Note
above.
85 for amplifiers having an amplifier in the feedback path
including bias control means for an electrode of such
amplifier.
86 for amplifiers having a variable impedance in a feedback
control path varied by a separate control path.
137 for amplifiers having bias control means including an
oscillator in the control means. See (3) Note above.
143 for amplifiers having a thermally responsive impedance
which may be controlled from an external control source.
144 for amplifiers having a variable impedance for the
signal channel controlled by a separate control path which
may be from an external source.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 309 for miscellaneous circuits
including bias voltage control means for amplitude limiting.
333, Wave Transmission Lines and Networks, subclass 15, 16
and 17.1+ for pilot line, pilot current and automatically
controlled passive wave transmission systems.
367, Communications, Electrical: Acoustic Wave Systems and
Devices 14, for means means where including the detector or
other related means of the seismic system, per se. See (1)
Note above.
455, Telecommunications, particularly 232.1 and 341+, for
similar subject matter in radio receivers.
Subclass:
131
This subclass is indented under subclass 129. Subject matter
wherein the bias control voltage is applied to an electrode
of the amplifying device separate and distinct from the
electrodes to which the signal input is applied.
(1) Note. Subject matter as above in which the separate and
distinct electrode to which the bias voltage is applied is
the screen grid or anode of a vacuum tube amplifying device
is not classified herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
128 for subject matter as above in which the separate and
distinct electrode to which the bias voltage is applied is
the screen grid or anode of a vacuum tube amplifying device.
Subclass:
132
This subclass is indented under subclass 129. Subject matter
wherein the "means to control the bias voltage" is derived
from the electrical signal channel through a frequency
selective means.
SEE OR SEARCH THIS CLASS, SUBCLASS:
52 for pilot frequency control amplifiers including subject
matter wherein the pilot control is derived from the signal
channel by frequency selective means.
85 for amplifiers having an amplifier in the feedback path
including those having bias voltage control which may be
derived by frequency selective means.
86 for amplifiers having a variable impedance means in the
signal feedback path controlled by a separate control which
may be derived by a frequency selective means from the signal
channel.
109 for signal feedback amplifiers having frequency
responsive means in the feedback path.
143 for amplifiers having thermally responsive impedance
which may be controlled by a voltage derived through a
frequency selective means from the signal channel.
144 for amplifiers having a variable impedance for the
signal channel controlled by a separate control path, wherein
the control voltage may be derived from the signal channel by
a frequency responsive means.
Subclass:
133
This subclass is indented under subclass 129. Subject matter
including at least two stages of amplification (each stage as
defined in the class definition with at least two such stages
as defined in subclass 129) such that the input signal of
each stage except the first is the output signal of the
preceding stage and wherein the bias control for each of at
least two of the stages as defined in subclass 129 has some
characteristic or characteristics distinctive from the
other.
Subclass:
134
This subclass is indented under subclass 129. Subject matter
including at least two separate and distinct bias voltage
control means as therein defined, wherein the control
voltages are applied to input or gain control electrodes, and
which may be applied to a single amplifying device or to more
than one amplifying device.
(1) Note. The two separately developed bias control means
may be combined or compared or separately applied in some
manner as a single bias control means to a single electrode.
Subclass:
135
This subclass is indented under subclass 129. Subject matter
including means to limit the maximum amplitude of the bias
control voltage.
SEE OR SEARCH THIS CLASS, SUBCLASS:
11 for amplifiers having D.C.. reinsertion circuits.
138 for amplifiers with voltage delay for bias control where
the bias control is not effective until a predetermined
minimum voltage is reached where such minimum voltage is
fixed by biasing a rectifier or control discharge device so
that it will not conduct until such voltage is reached.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 309 for miscellaneous circuits with
amplitude limiting means.
329, Demodulators, appropriate subclasses for automatic
control of the bias of a demodulating element.
Subclass:
136
This subclass is indented under subclass 129. Subject matter
wherein "the bias control voltage" is derived from the input
circuit of the amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching for input-output
comparison including those amplifiers wherein a bias control
voltage for drift correction is developed from such
comparison means.
11 for amplifiers having D.C.. reinsertion circuits.
Subclass:
137
This subclass is indented under subclass 129. Subject matter
wherein the bias voltage control means includes an oscillator
which may be itself controlled by a bias voltage means and
from which a signal amplifier bias voltage is derived, or
from which a control voltage, usually constant, is derived.
SEE OR SEARCH THIS CLASS, SUBCLASS:
52 for amplifiers having pilot frequency control means.
130 for amplifiers including bias voltage control from a
source in a system external to and independent from the
amplifier. See (3) Note under subclass 130 above.
Subclass:
138
This subclass is indented under subclass 129. Subject matter
wherein the "bias voltage control means" includes a rectifier
or discharge device which is biased in such a manner that the
rectifier or discharge device will not conduct until a
predetermined voltage is reached, which imparts to the
control means a "voltage delay" action and wherein the
minimum voltage at which bias control begins may be
predetermined.
SEE OR SEARCH THIS CLASS, SUBCLASS:
134 for amplifiers having plural different bias voltages
provided by separate means including those with biased
rectifiers or discharge devices.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 309 for miscellaneous threshold
limiters of the active element type.
Subclass:
139
This subclass is indented under subclass 129. Subject matter
wherein "the bias voltage control means" includes an
electronic tube to control the bias voltage which tube may be
a gas tube or vacuum tube having a means for control thereof
while the tube is in operation.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching input-output
comparison including those with electronic tubes for
control.
11 for amplifiers having D.C.. reinsertion circuits.
85 for amplifiers having amplifiers in the feedback path
including bias control for the feedback amplifier.
86 for feedback amplifiers having a variable impedance in
the feedback path varied by a separate control means,
including those wherein the variable impedance is an
electronic tube.
95 and 110, for signal feedback amplifiers with nonlinear
impedance which may be an electronic tube.
96 for signal feedback amplifiers wherein the signal
amplifier has bias voltage control means, including
amplifiers with an electron tube in such bias control means.
114 for amplifiers with oscillators supplying or controlling
the bias.
123 for push-pull amplifiers having bias voltage control
means including those with electronic tubes, in the bias
control means.
134 for amplifiers with plural different bias voltages
including electronic tube.
138 for amplifiers controlled by biased rectifiers or
discharge devices.
145 for amplifiers having an electronic tube or diode as a
variable impedance for the signal channel, controlled by a
separate control path.
164 for amplifiers with an electronic tube or diode in the
interstage coupling. See the search notes thereunder.
296 for semiconductors amplifiers including those with other
transistors for bias control.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
appropriate subclasses, for electronic tubes in voltage
magnitude control circuits generally.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 530 for miscellaneous electron tube
circuits with bias control means.
333, Wave Transmission Lines and Networks, subclass 14 for
amplitude compression and expansion systems, subclasses 15
and 16 for pilot signal controlled systems, 17.1+ for
automatically controlled systems and 213+ for negative
resistance or reactance active element networks.
Subclass:
140
This subclass is indented under subclass 129. Subject matter
combined with a rectifier in "the bias voltage control
means".
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers having periodic switching input-output
comparison.
11 for amplifiers having D.C.. reinsertion circuits.
52 for pilot frequency controlled amplifiers.
85 for amplifiers having amplifiers in the feedback path
including those with bias voltage control having rectifiers
in the control means.
86 for amplifiers having variable impedance in the feedback
path controlled by a separate control path.
95 and 110, for signal feedback amplifiers having nonlinear
means which may be a diode.
96 for signal feedback amplifiers wherein the signal
amplifier is provided with bias control including such bias
control containing a rectifier.
123 for push-pull amplifiers including those having bias
control means with rectifiers therein.
134 for amplifiers having plural different bias voltages
provided by separate means including those having biased
rectifiers in the control circuit.
138 for amplifiers having bias voltage control means
including a biased rectifier or discharge device.
145 for amplifiers having an electronic tube or diode as a
variable impedance for the signal channel controlled by a
separate control path.
164 for amplifiers having a diode in the interstage coupling
(see search notes under subclass 164).
254 and 278+, for semiconductor amplifiers having signal
volume level control.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 330 for miscellaneous
electron tube circuits with amplitude limiting and including
a rectifier.
363, Electric Power Conversion Systems, appropriate
subclasses for rectifier circuits.
Subclass:
141
This subclass is indented under subclass 129. Subject matter
wherein "the bias voltage control means" includes a circuit
of resistive and reactive elements, usually of resistive and
capacitive elements, which serves to filter or "smooth out"
the D.C.. bias voltage applied for control purposes to the
amplifier device and wherein specific details or distinctive
characteristics of such circuit are claimed.
(1) Note. Excluded from this subclass are the resistive
capacitive networks for self-biasing a vacuum tube amplifying
device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
142 for resistive capacitive networks for self-biasing a
vacuum tube amplifying device
143 for amplifiers having a thermally responsive impedance
element including those with separate control thereof.
144 for variable impedance for signal channel controlled by
separate control path.
199 for amplifiers and their power or bias voltage supply.
254 and 278+, for semiconductor amplifiers having signal
amplitude (volume level) control.
290 for semiconductor amplifiers having D.C.. feedback for
bias control.
296 and 297, for semiconductor device bias or power supply
circuitry.
SEE OR SEARCH CLASS:
320, Electricity: Battery or Capacitor Charging or
Discharging, 166 for charging or discharging a capacitor,
per se.
333, Wave Transmission Lines and Networks, 138, for passive
time delay networks, subclasses 181+, for smoothing type
passive filter networks.
363, Electric Power Conversion Systems, 44 for conversion
systems including D.C. smoothing filter networks.
455, Telecommunications, 234.1 for automatic volume control
in radio receivers; and subclass 343 for particular power or
bias supply for radio receivers.
Subclass:
142
This subclass is indented under subclass 129. Subject matter
involving a vacuum tube amplifying device whose input
electrode bias voltage and/or bias control voltage for the
same amplifying device is supplied from a resistive circuit
network in the cathode to ground path of the vacuum tube
amplifying device whereby the plate current flowing through
such resistor, which is usually by-passed for signal current
frequencies, develops a D.C.. bias voltage at the cathode.
(1) Note. The subject matter in this subclass includes both
adjustable self-biasing means cathode circuit self-biasing
means, per se, without an adjustable feature, for vacuum tube
amplifying device input electrodes. Input electrode bias
means without a control feature is classified elsewhere.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for amplifiers having series energized amplifiers
devices.
87 for cathode impedance feedback.
203 and 204, for input electrode biasing. See (1) Note
above.
254 and 278+, for semiconductor transistor amplifiers having
signal amplitude (volume level) control.
290 for semiconductor amplifiers having D.C.. bias control
feedback for stabilization.
296 and 297, for semiconductor amplifiers involving bias or
power supply circuitry.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 530 for miscellaneous electron tube
circuits with particular bias means.
Subclass:
143
This subclass is indented under the class definition.
Subject matter wherein the amplifier contains in its circuit
an impedance element whose impedance value is responsive to
the temperature changes therein by reason of the heat
generated by the current flow therethrough, or the ambient
temperature of the impedance element, or whose impedance
value may be changed by separate electrical control means or
other heat control means.
(1) Note. Heat responsive impedance elements are species of
nonlinear impedance elements and, as such, when appearing in
a cathode impedance feedback circuit or generally in the loop
path of a feedback amplifier are not in this subclass.
Nonlinear impedances, including thermal impedances, in a
feedback path which are varied by separate control means are
classified elsewhere. Thermally responsive impedance means
form a control means and when appearing in the voltage or
power supply circuits of a push-pull amplifier are classified
elsewhere in this class; and when appearing in the power
supply or bias supply circuits, as for example, in the
circuit from the voltage power supply to the anode or screen
grid or in the bias supply circuit so as to control the bias
of a vacuum tube amplifier device, classification is not
herein but in the appropriate subclass of this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
86 for nonlinear impedances, including thermal impedances,
in a feedback path which are varied by separate control
means. See (1) Note above.
95 and 110, for heat responsive impedance elements when
appearing in a cathode impedance feedback circuit or
generally in the loop path of a feedback amplifier. See (1)
Note above.
123 for thermally responsive impedance means forming a
control means and appearing in the voltage or power supply
circuits of a push-pull amplifier.
127 when appearing in the power supply or bias supply
circuits, as for example, in the circuit from the voltage
power supply to the anode or screen grid or in the bias
supply circuit so as to control the bias of a vacuum tube
amplifier device. See (1) Note above.
144 for variable impedance for the signal channel controlled
by separate control path.
157 appropriate subclasses thereunder for amplifier
interstage coupling which may include a nonlinear device
other than one thermally responsive, particularly subclass
164, for electronic tube or diode, and subclass 174, for
electromechanical transducer (e.g., piezo-electric crystal)
in the interstage coupling, and subclass 183, for a nonlinear
device generally (other than thermally responsive) in a D.C..
interstage coupling circuit.
185 for nonlinear impedance elements, other than thermally
responsive, in amplifier input circuits.
192 for nonlinear impedance elements, other than thermally
responsive, in amplifier output circuits.
256 272 and 289+, for semiconductor amplifiers with
transistor temperature control.
296 and 297, for semiconductor amplifiers involving bias or
power supply circuitry.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
subclass 294 for thermally responsive impedance means for
voltage magnitude control, generally.
336, Inductor Devices, appropriate subclasses for inductor
structure particularly subclass 30, for condition responsive
inductor adjusting means, including those responsive to
thermal conditions.
338, Electrical Resistors, 20 for resistors whose value is
responsive to the current therethrough or the voltage
thereacross and subclasses 25+ for resistors whose value
varies in response to ambient temperature conditions.
361, Electricity: Electrical Systems and Devices, subclass
282 for thermally responsive condensers, per se.
Subclass:
144
This subclass is indented under the class definition.
Subject matter wherein there is provided for the signal
transmission path a variable impedance element or circuit
which may be a variable resistance, or reactance, whose
impedance is controlled by a separate control means.
(1) Note. Examples of control of variable impedances
classified in this and indented subclasses are; a control
voltage secured from the signal output which may be
rectified, filtered and applied to a biased diode or to the
control electrode of an electronic tube to vary its
impedance, or to control an electric motor which may vary a
potentiometer or adjustable reactance in the signal path.
(2) Note. Considering the signal coupling means as a four
terminal network the "variable impedance" of the subclass may
be in series between corresponding terminals or in shunt
across the signal transmission path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
52 for amplifiers having pilot frequency control means.
70 for series energized vacuum tube amplifiers.
85 for signal feedback amplifiers having an amplifier in the
feedback path.
86 for signal feedback amplifiers having a variable
impedance in the feedback path varied by a separate control
path.
95 and 110, for signal feedback amplifiers having a
nonlinear impedance in the feedback path.
96 for signal feedback amplifiers having means to control
the amplifier bias voltage.
108 for potentiometer common to signal and feedback paths.
127 for amplifiers having control of power supply or bias
voltage, particularly subclasses 138, 139, and 140.
143 for thermally responsive impedance in the signal path
including those varied by a voltage or other means from a
separate control path.
155 for amplifiers having unicontrol coupling.
164 for cascaded amplifiers having an electronic tube or
diode in an interstage coupling circuit.
174 for cascaded amplifiers having an electromechanical
transducer (e.g., piezo-electric crystal) in an interstage
coupling path.
183 for cascaded amplifiers having a nonlinear device in a
D.C.. interstage coupling.
185 for variable impedance in amplifier input networks.
192 for variable impedance in amplifier output networks.
293 and 296, for series energized semiconductor amplifiers.
299 for combined diverse type semiconductors where one may
be a variable impedance for the signal transmission path.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
subclasses 234-289 for transformer and impedance systems
for voltage magnitude control.
324, Electricity: Measuring and Testing subclass 98, 99+,
and 101 for electrical measuring and testing circuits having
bridges with variable impedances thereon, which are varied by
a separate control means.
333, Wave Transmission Lines and Networks, appropriate
subclasses particularly subclass 14, 15, 16, 17.1+, 81, and
213+ for wave transmission systems with variable impedance in
the wave transmission path.
334, Tuners, appropriate subclasses for tuners, per se.
336, Inductor Devices, appropriate subclasses for the
structure of variable inductors.
338, Electrical Resistors, appropriate subclasses for the
structure of variable resistance devices.
361, Electricity: Electrical Systems and Devices, 277 for
variable condenser structure.
Subclass:
145
This subclass is indented under subclass 144. Subject matter
wherein the variable impedance means is an electron tube,
either vacuum tube or gaseous which has a control means
effective during operation of the tube, or a diode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for series energized vacuum tube amplifying devices.
85 for signal feedback amplifiers having an amplifier in the
feedback path.
138 139 and 140, for amplifiers having means to control the
input electrode bias voltage including respectively, biased
rectifiers or discharge devices, electronic tube, or
rectifier in the bias control circuit.
164 for cascaded amplifiers having an electronic tube or
diode in the interstage coupling circuit.
185 for amplifier input coupling networks which may have an
electronic tube or diode as an impedance therein.
192 for amplifier output coupling networks which may have an
electronic tube or diode impedance therein.
299 for combined diverse type semiconductors where one of
the semiconductors may be a diode or transistor impedance for
the signal transmission path.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
subclass 227 and 291 for discharge devices on voltage
magnitude control systems generally.
333, Wave Transmission Lines and Networks, 213 for negative
resistance and/or reactance networks of the active element
type.
334, Tuners, 14 for a tuner unit in which a reactance tube
is used.
Subclass:
146
This subclass is indented under the class definition.
Subject matter wherein the four arms of a Wheatstone bridge
comprise four impedances of the amplifier circuit in such
manner that at least one of the four impedances of the bridge
is the discharge path of the amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
72 for series energized vacuum tube amplifying devices with
at least two of the devices arranged in the arms of a
bridge.
76 for amplifiers for compensating for interelectrode
impedance (neutralization) by feedback where the input-output
interelectrode impedance coupling and compensating circuits
may be arranged in a balanced bridge.
81 for push-pull feedback amplifiers including plural stages
which may have a bridge-like arrangement.
118 for push-pull vacuum tube amplifiers including those
having plural stages with a bridge-like arrangement.
175 for interstage coupling circuits including bridge
networks.
273 for push-pull semiconductor amplifiers including those
with plural stages presenting a structure similar to a
bridge.
293 and 296, for plural stage semiconductor amplifiers
series energized which may include bridge arrangements.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
subclass 252, 333, and 365 for various impedance bridge
arrangements, for voltage magnitude or phase control; see
also the search notes under the above subclasses.
333, Wave Transmission Lines and Networks, subclass 169 for
wave filters having a Wheatstone bridge arrangement. See also
the search notes thereunder.
Subclass:
147
This subclass is indented under the class definition.
Subject matter wherein at least two separate and independent
sources of signal energy are coupled to the input of the
amplifying device.
(1) Note. Where each of the separate sources has an
amplifying device in its input circuit before being jointly
coupled to an amplifying device, classification is not
herein.
(2) Note. The two separate sources need not operate to feed
signal energy to the amplifying device simultaneously but may
operate selectively, for example, as by switching the sources
whereby one is feeding the amplifying device at a time.
(3) Note. A balanced circuit is treated as a single source
in this class. See the definition and notes under subclass
116 above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers having distributed parameter type coupling
means.
69 for sum and difference amplifiers.
74 for series energized vacuum tube amplifiers having plural
separate inputs to series devices.
84 for signal amplifiers having plural amplifier channels.
124 see (1) Note above, also for plural separate inputs to
plural channels.
185 for amplifiers having significant input networks.
252 for semiconductor amplifiers having plural inputs or
plural channels.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 18
and 43+ for electrical transmission or interconnection
systems having plural supply circuits or sources.
Subclass:
148
This subclass is indented under the class definition.
Subject matter wherein at least two separate signal output
circuits are coupled from the output electrode or element of
the signal amplifying device, for coupling to separate load
devices.
(1) Note. Where at least two of the signal output circuits
each contain a signal amplifying device for amplifying the
signal, classification is not herein but with plural signal
amplifier channels.
(2) Note. Any one or more of the separate signal output
circuits may be switched selectively; operation need not be
simultaneous for classification in this subclass.
(3) Note. A balanced circuit is treated as a single load in
this class. See definition and notes for subclass 117
above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers having distributed parameter type coupling
means.
73 for amplifiers having series energized amplifying devices
having plural separate output circuits.
84 for signal feedback amplifiers having plural amplifier
channels.
124 for plural signal amplifier channel, also for separate
outputs from plural channels. see (1) Note above.
192 for amplifiers with significant signal output circuit
networks.
252 for semiconductor amplifiers with plural separate signal
outputs or plural channels.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 11
for electric transmission or interconnection systems having
plural load circuit systems.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous circuits having plural outputs.
329, Demodulators, 316 for plural outputs in frequency
demodulator and subclass 348 for plural outputs in an
amplitude demodulator.
333, Wave Transmission Lines and Networks, 100 for wave
transmission lines and networks having branched circuits.
Subclass:
149
This subclass is indented under the class definition.
Subject matter wherein the signal has a hum or noise
component inadvertently introduced therein, as where there is
ineffective filtering of a rectified A.C. power supply or
bias, and wherein such objectional component is removed or
reduced by the same hum or noise component introduced into
the signal path of the amplifier in such manner as to oppose
the objectional signal component, thereby removing it from,
or reducing it in, the output signal.
(1) Note. Where such component is removed or reduced by
negative feedback classification is elsewhere.
SEE OR SEARCH THIS CLASS, SUBCLASS:
75 where such components of this subclass (149) are removed
or reduced by negative feedback. See (1) Note above.
114 for amplifiers having unrectified A.C. power supply
including those with means to eliminate hum.
118 for push-pull amplifiers which include means for
opposing noise, hum, or other unwanted components
inadvertently present with the signal, and wherein the
compensation is inherent in the push-pull arrangement, per
se.
124 for plural channel amplifiers including those wherein an
unwanted component in the signal is separately amplified and
opposes the unwanted component in a channel which includes
the signal and the unwanted component.
150 for cascaded amplifying devices of different
characteristics including those wherein the characteristics
of one stage compensate for those of another.
151 for cascaded amplifying devices with means to by-pass a
stage wherein a feed forward component may oppose the same
component in the signal path.
199 for amplifiers with power or bias voltage supply
including filters to eliminate hum, etc..
296 and 297, for semiconductor amplifiers with bias or power
supply circuitry.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems, 94 for
discharge device load systems having cathode or cathode
heater power supply, with or without anode power supply, but
excluding control electrode supply, including those having
means for hum elimination, etc..
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 549 for miscellaneous
circuits with power supply and hum prevention or elimination
means.
333, Wave Transmission Lines and Networks, 167 for wave
filters, per se, which may be used to eliminate a frequency
component, particularly subclasses 181+, for smoothing
filters for power supply.
363, Electric Power Conversion Systems, 39 for electrical
conversion systems including means to eliminate frequency
components.
Subclass:
150
This subclass is indented under the class definition.
Subject matter including at least two stages of amplification
(each stage as defined in the class definition and each stage
having a vacuum tube amplifying device) such that, the input
signal for each stage, except the first, is the output signal
of the preceding stage, and wherein at least one of the
cascaded amplifying devices has a significant difference in
its characteristics such as a difference in the number of
electrodes, or where the construction of each of at least two
of the tubes is such that there is a difference in the tube
characteristics, or where because of differences in biasing
or energizing voltages the tube characteristics are
different.
(1) Note. Different types of vacuum tubes representing a
genus or class and provided for above such as traveling wave
tubes and magnetrons or traveling wave tubes and secondary
emission tubes when claimed in cascade are classified
elsewhere (see the search this class, subclass notes below)
Where vacuum tubes, are different in structural
characteristics or some other feature, but all of the plural
tubes fall within one of the genus types provided for above,
as for example traveling wave tubes classification is with
the genus type and not in this subclass.
(2) Note. Beam power tubes, broadly claimed with no other
distinctive characteristics, when combined in cascade with
another vacuum tube such as an ordinary triode are classified
in this subclass and not in subclass 3 or subclasses 44+
above.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for different types of vacuum tubes representing a genus
or class and provided for above such as traveling wave tubes
and magnetrons or traveling wave tubes and secondary emission
tubes when claimed in cascade. Where vacuum tubes, are
different in structural characteristics or some other
feature, but all of the plural tubes fall within one of the
genus types provided for above, as for example traveling wave
tubes classification is with the genus type and not in this
subclass (150) nor in subclass 3.
6 for magnetrons.
42 for traveling wave tubes and secondary emission tubes.
43 for traveling wave tubes.
70 for series arranged vacuum tube amplifiers including
cascaded amplifiers so arranged.
310 for cascaded semiconductor amplifiers, particularly
subclass 311 for cascaded semiconductors of different
characteristics.
Subclass:
151
This subclass is indented under the class definition.
Subject matter wherein means are provided to by-pass all or a
part of the signal across the amplifier or of one or more
stages of a cascade amplifier.
(1) Note. For classification herein the by-pass means must
be free of any amplifying device. Subject matter having such
additional amplifying device is not in this subclass.
(2) Note. This subclass includes subject matter involving a
cascaded amplifier, for switching an amplifier device in or
out of the cascaded arrangement.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers having distributed parameter coupling
means, particularly subclass 54 for distributed amplifiers.
70 for series energized amplifiers including cascaded
amplifiers having such arrangement.
84 for signal feedback amplifiers having plural amplifier
channels.
88 92, and 98+, for cascaded amplifiers having signal
feedback.
120 for cascaded push-pull amplifiers.
124 for by-pass means having additional amplifying device.
See (1) Note above.
133 for cascaded amplifiers having different bias control
for different stages.
145 for amplifiers having a separately controlled tube in
the signal path.
147 and 148, for amplifiers having plural signal inputs and
plural signal outputs, respectively.
157 for amplifier interstage couplings, per se, particularly
subclass 164, for an electronic tube or diode in the coupling
circuit.
310 for cascaded semiconductor amplifiers.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 100 for wave
transmission passive network branched circuits.
Subclass:
152
This subclass is indented under the class definition.
Subject matter including at least three stages of
amplification (each stage as defined in the class definition)
such that, the input signal for each stage, except the first,
is the output signal of the preceding stage; and where two of
the interstage coupling means between successive amplifying
devices have different characteristics.
(1) Note. The following are examples of subject matter
classified in this and indented subclasses: one device is
coupled from the plate and the other from the cathode; or one
coupling has a tuned circuit and the other has not; or both
couplings have circuits tuned to different frequencies or the
two couplings may be similar but contain an impedance element
or elements of one having different values from the
corresponding element, or elements in the other interstage
coupling.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for plural diverse type amplifying devices.
53 for amplifiers having distributed parameter type
coupling.
70 for series energized vacuum tube amplifiers.
88 92 and 98, for cascaded amplifiers including signal
feedback.
120 for interstage coupling between push-pull stages of an
amplifier.
133 for different bias control on different stages of a
cascaded amplifier.
150 for cascaded amplifiers with similar amplifying devices
having different characteristics.
151 for amplifiers with means to by-pass a stage.
157 for interstage coupling in an amplifier.
310 for plural stage cascaded semiconductor amplifiers.
SEE OR SEARCH CLASS:
323, Electricity: Power Supply or Regulation Systems,
appropriate subclasses for voltage magnitude and phase
control systems generally, with various transformer and
impedance networks to perform such functions.
333, Wave Transmission Lines and Networks, 24 for coupling
networks for wave transmission, generally.
Subclass:
153
This subclass is indented under subclass 152. Subject matter
wherein at least one of the interstage coupling means has a
cathode follower signal output.
(1) Note. If only the coupling of the last stage is a
cathode follower and none of the previous stages has a
cathode follower output, classification is not in this
subclass. For classification of cathode follower amplifiers
and analogous subject matter see search notes immediately
following.
SEE OR SEARCH THIS CLASS, SUBCLASS:
119 for push-pull vacuum tube amplifiers including cathode
followers.
168 and 172+, for amplifiers having a cathode follower in
the interstage coupling.
193 for amplifiers with cathode follower output coupling.
310 for cascaded semiconductor amplifiers which may have an
emitter follower stage analogous to cathode follower in a
cascaded vacuum tube amplifier.
Subclass:
154
This subclass is indented under subclass 152. Subject matter
wherein at least one of the interstage coupling means has a
signal coupling transformer or a resonant circuit contained
therein.
(1) Note. Stagger tuned amplifiers are classified in this
subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
56 for amplifiers having wave guide, cavity, or concentric
resonator coupling means.
120 for interstage coupling between push-pull amplifier
stages including transformer coupling and resonant means in
the coupling circuit.
165 for amplifiers having transformer interstage coupling.
302 for cascaded semiconductor amplifiers having frequency
responsive signal coupling means.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24 for wave
transmission coupling means, generally, including resonant
circuits and transformer coupling.
334, Tuners, appropriate subclasses for tuners, per se, and
especially 59 and 61+ for transformers used in a resonant
circuit.
Subclass:
155
This subclass is indented under the class definition.
Subject matter wherein two or more elements such as
resistors, reactors, etc.., of any coupling network or
different coupling networks, for transmission of the signal
in the amplifier are constructed and arranged so that
adjustment or control is simultaneous for such two or more
elements, such adjustment may be for a tuner, a
potentiometer, or any other means or any combination of such
means, in the coupling circuits or associated circuits.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 particularly subclass 56 for distributed parameter
coupling means including adjustment of such means.
65 for structure of circuit elements when in an amplifier
which may include the structure of adjustable circuit
elements.
108 for a potentiometer common to the signal and feedback
paths of an amplifier.
116 and 117, for amplifiers with balanced-to-unbalanced and
unbalanced-to-balanced coupling, respectively, which may
involve adjustable circuit elements.
120 and 122, for coupling of a push-pull amplifier which may
involve adjustable circuit elements in the coupling.
143 for amplifiers with a thermally responsive impedance.
144 for amplifiers having a variable impedance for the
signal channel controlled by a separate control path.
157 for amplifiers with interstage coupling which may have
an adjustable element in the coupling.
171 190 and 197, for transformer structure.
185 for amplifiers which may have an adjustable element in
the input coupling.
192 for amplifiers which may have an adjustable element in
the output coupling.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24, 81 and 219+
for coupling means, attenuators, or distributed parameter
type resonators, respectively, including those with variable
circuit elements.
334, Tuners, appropriate subclasses for tuners, per se.
336, Inductor Devices, appropriate subclasses for variable
inductor devices.
338, Electrical Resistors, appropriate subclasses for the
structure of rheostats, and resistors.
361, Electricity: Electrical Systems and Devices, 277 for
variable condensers.
Subclass:
156
This subclass is indented under the class definition.
Subject matter wherein the signal input is floating and is
applied between the control grid and cathode of a vacuum tube
amplifying device, with the cathode having an impedance
between it and ground which maintains the cathode voltage
above ground, by reason of the anode current flowing through
such impedance.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for series energized amplifiers including those having
signal coupling between cathode and grid similar to the
subject matter in this subclass.
87 for amplifiers having cathode impedance feedback
particularly subclass 89 for cathode coupling between
adjacent stages.
119 for push-pull amplifiers including coupling to the
cathode.
153 for amplifiers having interstage coupling to a cathode.
186 for amplifiers having input coupling to a cathode.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 589 for miscellaneous
electron tube circuits with bootstrap circuit means.
Subclass:
157
This subclass is indented under the class definition.
Subject matter wherein the amplifier is comprised of at least
two amplifying devices in cascade, the two being in direct
proximity in the cascaded circuit and wherein there are
significant details or distinctive characteristics of the
circuit by means of which the signal output of the preceding
amplifying device is coupled to the signal input of the
following cascaded amplifying device, or wherein the
parameters or electrical characteristics of the output of the
preceding device or the input of the following device, are
claimed.
(1) Note. Subject matter disclosing interstage coupling but
wherein only the output coupling of the first amplifying
device is claimed or wherein only the input coupling of the
following amplifying device is claimed is classified in this
and appropriate indented subclasses and not with input or
output coupling under subclasses 185+ or 192+, respectively.
(2) Note. The output of the preceding amplifying device of
the cascaded devices has an output electrode and a common
electrode for the signal and the input of the following stage
has an input electrode and a common electrode, to receive the
signal. Thus, there is involved a four terminal coupling
network between output (including common electrode) and input
(including common electrode) with usually two-series circuits
between output and input electrodes and between common
electrodes respectively and also shunt circuit elements often
between such series circuits.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for plural diverse type amplifying devices which may
involve interstage coupling between such devices.
53 for coupling of distributed parameter type which may be
interstage.
65 for structure of circuit elements, other than transformer
structure, which may be involved in interstage coupling.
70 for interstage coupling between cascaded series energized
tubes.
88 92, and 98+, for interstage coupling in cascaded feedback
amplifiers.
120 for interstage coupling in push-pull amplifiers.
133 for cascaded amplifiers having bias voltage control
which may involve interstage coupling.
143 for thermally responsive impedance which may be involved
in interstage coupling.
144 for variable impedance controlled by separate control
path which may be involved in interstage coupling.
150 for cascaded stages having amplifiers of different
characteristics with interstage coupling means.
151 for cascaded stages with means to by-pass a stage.
152 for diverse types interstage coupling in amplifiers
having plural cascaded stages.
155 for unicontrol of coupling means which may involve
interstage coupling.
156 for bootstrap coupling.
185 for amplifiers with input coupling networks. See (1)
Note above.
192 for amplifiers with output coupling networks. See (1)
Note above.
310 for plural stage cascaded semiconductor amplifiers,
involving interstage coupling.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24, for passive
coupling networks for wave transmission, generally.
Subclass:
158
This subclass is indented under subclass 157. Subject matter
wherein the signal derived from the preceding cascaded
amplifying device is coupled to the cathode electrode of a
following cascaded vacuum tube amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
88 and 91+, for amplifiers applying signal feedback to the
cathode.
89 for amplifiers having adjacent cascaded stages with
cathode-cathode coupling. See (1) Note thereunder.
119 for push-pull amplifiers with coupling to the cathode.
156 for bootstrap coupling where input signal is applied
directly between grid and cathode.
186 for input coupling to the cathode.
Subclass:
159
This subclass is indented under subclass 158. Subject matter
wherein the interstage coupling has a D.C.. conductive path
for signal current from the output electrode of the preceding
cascaded amplifying device to the input electrode of the
following device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
187 for amplifiers with D.C.. input coupling to the
cathode.
Subclass:
160
This subclass is indented under subclass 157. Subject matter
wherein the signal derived from the first of the two cascaded
amplifying devices is coupled to the screen grid or an
electrode other than the control grid or cathode, such as the
anode electrode or the suppressor grid of the following
cascaded amplifying device, which device is of the vacuum
tube type.
SEE OR SEARCH THIS CLASS, SUBCLASS:
64 for space charge grid tube amplifiers wherein the first
grid next to the cathode is biased positively with respect
thereto and the signal input is applied to the grid next in
succession from the cathode which is biased negatively with
respect to the cathode.
185 and 188+, for input coupling to a vacuum tube amplifying
device including input coupling to an electrode other than
the control grid or cathode.
SEE OR SEARCH CLASS:
324, Electricity: Measuring and Testing, subclass 124 for
amplifiers combined with an electrical measuring device
wherein the input is applied to the anode of the amplifying
device (e.g., inverted amplifier).
Subclass:
161
This subclass is indented under subclass 160. Subject matter
wherein the coupling has a D.C.. conductive path for signal
current from the output electrode of the preceding amplifying
device to the input, electrode of the following of the two
cascaded vacuum tube amplifying devices.
SEE OR SEARCH THIS CLASS, SUBCLASS:
191 for a D.C.. amplifier input coupling which may be to an
electrode of a vacuum tube amplifying device other than the
control grid or cathode.
Subclass:
162
This subclass is indented under subclass 157. Subject matter
wherein the coupling between the two cascaded amplifying
devices is from a grid, such as the screen grid, suppressor
grid or control grid, or from between such a grid and an
anode of the preceding amplifier device (of the vacuum tube
type) of the two cascaded devices.
SEE OR SEARCH THIS CLASS, SUBCLASS:
42 for amplifiers having secondary emission amplifier
devices wherein the output may be from a secondary emissive
electrode.
192 and 195, for output coupling from a grid, such as the
screen grid, suppressor grid or control grid or between such
a grid and the anode.
SEE OR SEARCH CLASS:
324, Electricity: Measuring and Testing, subclass 124 for
inverter amplifiers combined with measuring means where the
output is from the control grid.
Subclass:
163
This subclass is indented under subclass 162. Subject matter
wherein the coupling has a D.C.. conductive signal path from
the grid or from between the grid and anode of the preceding
of the two cascaded amplifying devices (of the vacuum tube
type) to the following device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
198 for D.C.. output coupling which may involve coupling
from a grid or from between a grid and the anode.
Subclass:
164
This subclass is indented under subclass 157. Subject matter
in which the coupling circuit between the two cascaded stages
has at least one path which includes an electronic discharge
tube (which may be a gas tube or vacuum tube having control
means effective during operation of the tube) or which
includes a diode element which may be a glow tube, a
rectifier vacuum tube diode or a dry rectifier diode, etc..
(1) Note. The electronic tube or diode performs some
function, such as an impedance, other than serving as an
additional amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
138 for control of bias or power supply voltage by a biased
rectifier or discharge device.
139 and 140, for an amplifier including an electronic tube
or rectifier, respectively, to control the input or gain
control electrode bias.
143 where the diode or electronic tube is a thermally
responsive element.
145 where the diode or electronic tube is a variable
impedance controlled by a separate control path.
185 for amplifier input circuits including any with an
electronic tube or diode, in the input circuit (other than as
a preceding amplifying stage).
192 for amplifier output networks which may include an
electronic tube or diode (other than as an amplifying
stage).
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 213 for negative
resistance and/or reactance networks which have an active
element including electron tubes or diodes, as such active
elements.
Subclass:
165
This subclass is indented under subclass 157. Subject matter
wherein the the signal coupling between the two cascaded
amplifying device stages is by means of at least one
transformer.
SEE OR SEARCH THIS CLASS, SUBCLASS:
120 for interstage coupling in push-pull amplifiers
including transformer coupling.
122 for input or output coupling in push-pull amplifiers
including transformer coupling.
154 for transformer coupling in plural stage cascaded vacuum
tube amplifiers with at least two interstage coupling
networks which have some different characteristic.
188 for transformer coupled amplifier input circuits.
195 for transformer coupled amplifier output circuits.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 177 for wave
transmission transformer coupled circuits of the passive
type, generally.
334, Tuners, 59 and 61+ for tuners having a transformer in
the resonant circuit.
336, Inductor Devices, appropriate subclasses, for
transformer structure.
Subclass:
166
This subclass is indented under subclass 165. Subject matter
wherein, between the primary and secondary of the
transformer, there is an additional capacitive or inductive
reactor element which carries part of the signal current
coupled between the two devices.
Subclass:
167
This subclass is indented under subclass 165. Subject matter
wherein additional impedance which may be inductive,
capacitive or resistive is included in either the primary or
secondary winding circuit of the transformer which couples
the signal between the two cascaded amplifier devices.
SEE OR SEARCH THIS CLASS, SUBCLASS:
189 for transformer input coupling with additional impedance
connected to the primary or secondary winding circuit.
196 for transformer output coupling with additional
impedance connected to the primary or secondary winding
circuit.
Subclass:
168
This subclass is indented under subclass 165. Subject matter
wherein means are provided to derive the signal from the
cathode of the preceding amplifying device (of the vacuum
tube type).
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for series energized tubes which may have a cathode
follower output.
88 and 91, for cascaded amplifiers having signal feedback to
the cathode.
117 for amplifiers having unbalanced-to-balanced coupling
including phase splitters with cathode coupled output.
119 for push-pull amplifier involving coupling from the
cathode.
153 for different interstage coupling in cascaded amplifiers
including a cathode follower stage.
156 for bootstrap coupled amplifiers.
172 for interstage coupling from the cathode for other than
transformer coupling.
193 for output networks from the cathode of the amplifying
device.
250 for semiconductor amplifiers having emitter signal
output analogous to cathode follower output.
Subclass:
169
This subclass is indented under subclass 165. Subject matter
wherein means are provided for adjusting the inductance of
either the primary or secondary winding or the mutual
inductance between the primary and secondary winding, in the
latter case, for example, by varying the position of the
primary or secondary windings or parts thereof relative to
each other.
SEE OR SEARCH CLASS:
334, Tuners, 61 for tuners having mutual inductance variable
means.
336, Inductor Devices, appropriate subclasses particularly
115 for adjustable coupling by relatively moving coils, and
subclasses 130+ for relatively movable coil and core to vary
the inductance. Class 336 is the general class for the
structure of inductors including means to vary the inductance
and mutual inductance.
Subclass:
170
This subclass is indented under subclass 165. Subject matter
combined with shielding means, for the transformer, or parts
thereof.
(1) Note. Under interstage coupling, shielding and the
structure of shielding are classified separately (subclass
170) from other structure of transformers (subclass 171).
Under input and output coupling no separate provision is made
for shielding so that all structure of transformers in input
or output amplifier coupling including shielding is
classified in subclasses 190 and 197, below respectively.
SEE OR SEARCH THIS CLASS, SUBCLASS:
68 for shielding combined with amplifiers or with circuit
elements of amplifiers, generally.
190 for amplifier input coupling including transformer
structure which may include shielding.
197 for amplifier output coupling including transformer
structure which may include shielding.
SEE OR SEARCH CLASS:
174, Electricity: Conductors and Insulators, 35, shielded or
screened, for shielding electrical elements, generally. See
the search notes thereunder.
336, Inductor Devices, 84 for shielding of inductors,
generally. See the search notes thereunder.
Subclass:
171
This subclass is indented under subclass 165. Subject matter
involving the structure of the transformer coupling the
signal between the two cascaded stages.
SEE OR SEARCH THIS CLASS, SUBCLASS:
65 for structure of amplifier circuit elements other than
transformers involved with an amplifier system.
190 for the structure of transformers in amplifier input
coupling.
197 for the structure of transformers in amplifier output
coupling.
SEE OR SEARCH CLASS:
336, Inductor Devices, appropriate subclasses for transformer
structure generally.
Subclass:
172
This subclass is indented under subclass 157. Subject matter
wherein the signal output is coupled form the cathode
electrode of the preceding vacuum tube amplifier device of
the two cascaded amplifying devices, to the input of the
following amplifier device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for series energized vacuum tube amplifiers which may
have an output circuit from the cathode.
88 and 91, for cascaded vacuum tube amplifying devices with
signal feedback from the cathode.
89 for amplifiers having adjacent cascaded stages with
cathode-cathode coupling.
117 for amplifiers with unbalanced-to-balanced coupling
including phase splitters with cathode output coupling.
119 for push-pull amplifiers with coupling from the
cathode.
153 for plural stage cascaded vacuum tube amplifying devices
with different coupling between stages including a cathode
follower stage.
156 for bootstrap coupling.
168 for interstage transformer coupling from the cathode.
193 for amplifier output coupling networks from the cathode
of the amplifying device (cathode followers) see the notes
and search notes thereunder.
250 for semiconductor amplifiers having emitter output
analogous to cathode follower output.
Subclass:
173
This subclass is indented under subclass 172. Subject matter
wherein the coupling between the two cascaded amplifying
devices is a D.C.. conductive path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
194 for vacuum tube amplifier device output coupling
circuits with D.C.. coupling from the cathode.
Subclass:
174
This subclass is indented under subclass 157. Subject matter
wherein the coupling circuit between the two cascaded
amplifier devices includes means to convert the electric
signal to mechanical vibrations and means further to convert
the mechanical vibrations back to electric signals, such
means, generally, serving as either time or phase delay means
or means to determine the transmission frequency of the
coupling network.
(1) Note. The electromechanical transducer means in this
subclass is distinguished from subject matter of subclass 60
above, wherein the amplifying device itself includes a
magnetostrictive means electromechanical transducer. In this
subclass, the electrical signal energy is not used to control
another source of electrical energy applied to the
transducer, but herein the electric signal, in being
transmitted, is converted to mechanical energy and back to
electrical energy.
SEE OR SEARCH THIS CLASS, SUBCLASS:
60 for amplifiers having magnetostrictive means.
185 for amplifier input circuits including any having an
electromechanical transducer. See (1) Note under subclass
157.
192 for amplifier output circuits including any having an
electromechanical transducer. See (1) Note under subclass
157.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 148, 186, and 187+
for delay lines using electromechanical transducers, and for
wave filters using electromechanical transducers and
piezo-electric types of such transducers, respectively. See
the search notes under these subclasses.
Subclass:
175
This subclass is indented under subclass 157. Subject matter
wherein the coupling includes a network having four impedance
branches connected in series to form a closed circuit, two
nonadjacent junction points serving as input terminals while
the remaining two junction points serve as output terminals.
SEE OR SEARCH THIS CLASS, SUBCLASS:
72 for plural amplifier devices having space discharge paths
in different arms of a bridge.
146 for Wheatstone bridge with amplifier in at least one
arm.
185 for amplifier input coupling including any with a
lattice or Wheatstone bridge network. See (1) Note under
subclass 157, above.
192 for amplifier output coupling including any with a
lattice or Wheatstone bridge network. See (1) Note under
subclass 157, above.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 74,
sections (1) and (2) of the definition.
Subclass:
176
This subclass is indented under subclass 157. Subject matter
wherein the coupling includes a T, H, or Pi circuit network.
SEE OR SEARCH THIS CLASS, SUBCLASS:
185 for amplifier input circuit networks including any with
a T, H, or Pi circuit network. See (1) Note under subclass
157, above.
192 for amplifier output circuit networks including any with
a T, H, or Pi circuit network. See (1) Note under subclass
157, above.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24, appropriate
subclasses thereunder for coupling circuits which may include
T, H, of Pi networks. See the notes and search notes under
Class 333, subclass 24.
Subclass:
177
This subclass is indented under subclass 157. Subject matter
wherein any path traced in series from the output electrode
of the preceding of the two cascaded amplifying devices to
the input electrode of the amplifier device of the following
stage contains at least one capacitor.
SEE OR SEARCH THIS CLASS, SUBCLASS:
120 for push-pull amplifiers with significant interstage
coupling which may include a blocking capacitor in such
coupling.
166 for amplifiers with interstage transformer coupling
having additional reactive coupling which may be a
capacitor.
185 and 186, for amplifier capacitor input coupling,
generally, and to a cathode, respectively.
192 and 193, for amplifier capacitor output coupling,
generally, and from a cathode, respectively.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24 for coupling
circuits generally, see notes and search notes under subclass
24.
Subclass:
178
This subclass is indented under subclass 177. Subject matter
wherein the series path between the output electrode of the
preceding of the two cascaded devices and the input electrode
of the succeeding device has a resistor of inductance in such
path in series with the coupling or blocking capacitor.
Subclass:
179
This subclass is indented under subclass 177. Subject matter
having in addition an inductor connected to the anode output
electrode of the preceding stage device or to the grid input
electrode of the following stage device, in shunt across the
signal transmission path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 appropriate subclasses for circuits in the anode power
supply or grid bias supply which may include an inductor. See
the search notes under subclass 199, below.
Subclass:
180
This subclass is indented under subclass 177. Subject matter
having in addition a resistance directly connected to the
anode output electrode from the anode power supply of the
preceding amplifier stage device and a resistance directly
connected to the input grid electrode of the following
amplifier stage device from the negative bias source or
ground, each resistance being in shunt across the signal
transmission path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 for power or voltage supply circuits to the anode or
grid electrodes which may have resistors therein. See the
search notes under subclass 199, below.
Subclass:
181
This subclass is indented under subclass 157. Subject matter
wherein the series coupling from the output electrode of the
preceding amplifier device to the input electrode of the
following amplifier device of the two cascaded stages has a
D.C.. conductive path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for periodic switching for input-output comparison
including drift corrected D.C.. amplifiers.
10 for modulator-demodulator amplifiers for amplifying D.C..
signals.
53 for amplifiers having distributed parameter coupling
which may include D.C.. interstage coupling.
70 for series energized amplifiers.
121 for push-pull amplifiers having D.C.. interstage
coupling.
125 for plural amplifier channels involving a D.C.. and an
A.C. channel.
159 for interstage D.C.. coupling to the cathode.
161 for D.C.. interstage coupling to the screen grid or
electrode other than control grid or cathode.
163 for D.C.. interstage output coupling from a grid or
between a grid and the anode.
173 for D.C.. interstage coupling from the cathode.
187 for input D.C.. coupling to the cathode.
191 for D.C.. input coupling, generally.
194 for D.C.. output coupling from the cathode.
198 for D.C.. output coupling, generally.
289 for D.C.. conductively coupled cascaded semiconductor
amplifiers.
293 and 296, for series energized cascaded semiconductor
amplifiers.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24 for wave
transmission coupling, generally. See, also, search notes
under subclass 24.
Subclass:
182
This subclass is indented under subclass 181. Subject matter
wherein the series coupling D.C.. conductive path between the
output electrode of the preceding amplifying device and the
input electrode of the following amplifying device contains
therein a reactive element, such as an inductor or parallel
to a D.C.. conductive element in the series path there is a
capacitive reactive element.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers with distributed parameter coupling which
may involve a D.C.. conductive path including a reactive
element.
107 for signal feedback amplifiers having a phase shift
network in the loop path.
121 for push-pull amplifiers having D.C.. interstage
coupling including any with series reactor element.
143 for amplifiers having a thermally responsive impedance.
144 for amplifiers having a variable impedance in the signal
path controlled by a separate control path.
166 for transformer coupled amplifier stages including a
D.C.. reactive element (inductor coil) jointing the primary
and secondary windings.
175 for amplifiers having a lattice or Wheatstone bridge
network in the interstage coupling circuit.
176 for amplifiers having a T, H, or Pi network in the
interstage coupling.
302 for semiconductor amplifiers having frequency responsive
means in the signal transmission path.
Subclass:
183
This subclass is indented under subclass 181. Subject matter
wherein the coupling contains a device whose impedance (which
may be resistive, capacitive, or inductive or any combination
of these) is such that the relationship of voltage across the
device to the current flow therein is nonlinear.
(1) Note. The device may be in shunt across the signal
transmission path, or in the D.C.. series path between the
vacuum tube amplifying devices, or in any other position in
the signal coupling circuit.
SEE OR SEARCH THIS CLASS, SUBCLASS:
86 for signal amplifiers with a variable impedance in the
feedback path which is varied by a separate control path.
95 for feedback amplifiers having a nonlinear impedance
means in the cathode circuit.
110 for feedback amplifiers having a nonlinear impedance
element in the loop path.
127 for nonlinear impedances involved in circuits for the
control of amplifier power supply or bias voltage.
143 for amplifiers having a thermally responsive impedance.
144 for amplifiers having a variable impedance for the
signal channel which is varied by a separate control path.
164 for cascaded amplifiers having an electronic tube or
diode in an interstage coupling circuit.
174 for cascaded amplifiers having an electromechanical
transducer such as a piezo-electric crystal in an interstage
coupling circuit.
185 or appropriate indented subclass for a nonlinear device
involved in the input coupling.
192 or appropriate indented subclass for a nonlinear device
involved in the output coupling.
299 for semiconductor amplifiers having a diverse type
semiconductor, which may be a nonlinear coupling impedance.
SEE OR SEARCH CLASS:
257, Active Solid-State Devices (e.g., Transistors,
Solid-State Diodes), appropriate subclasses for active
solid-state devices, per se, including subclass 115, 123 and
162 through 166 which are directed to devices involving
amplification.
307, Electrical Transmission or Interconnection Systems, 401
for nonlinear reactor systems.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous nonlinear transistor and electron tube
circuits.
333, Wave Transmission Lines and Networks, appropriate
subclasses for wave transmission networks which may involve
nonlinear impedance elements.
338, Electrical Resistors, 13 for nonlinear resistor
elements.
361, Electricity: Electrical Systems and Devices, 271 for
structure of a capacitor which may be nonlinear.
Subclass:
184
This subclass is indented under subclass 181. Subject matter
wherein the series coupling D.C.. conductive path between the
output electrode of the preceding amplifying device and the
input electrode of the following amplifying device of the two
cascaded amplifying devices contains therein a resistor.
Subclass:
185
This subclass is indented under the class definition.
Subject matter involving significant detail or distinctive
characteristics of the electrical circuit coupling a source
of signal energy to the input of the amplifying device; or
involving electrical characteristics of the source; or
involving input electrical parameters of the amplifying
device to which the signal input is coupled.
(1) Note. Subject matter in which a source is claimed by
name only as a specific art device, as for example, a
microphone, is classified with specific art device and not
with amplifiers. Subject matter in which the source device
may be broadly claimed, not by name, but by some distinctive
identifying feature thereof, as where the microphone source
is claimed as a "means for converting sound signals",
classification is not with amplifiers but with the
distinctive art device.
(2) Note. The term "generator" or "oscillator" in claims,
where either appears as a source of signal energy without
further qualification except an electrical characteristic
such as impedance, reactance etc.., is treated as a
generalized source of signal energy, and classification is
with amplifiers. Where specific details of the generator or
oscillator are claimed, classification is with the type of
generator established in the claims or with oscillators in
Class 331, Oscillators.
(3) Note. Amplifier subject matter disclosing an interstage
coupling but wherein only the input coupling to the
succeeding stage is claimed and no interstage coupling or
details to establish such coupling are claimed, is not
classified in this and indented subclasses. See the search
this class, subclass notes below for Interstage Coupling.
SEE OR SEARCH THIS CLASS, SUBCLASS:
65 for input coupling involving structure of any of the
input circuit elements.
74 for plural inputs to series energized tubes.
106 for amplifiers having feedback in series with the input
source.
108 for input coupling which may include a potentiometer
therein common to the signal and feedback paths.
116 for amplifiers with balanced input involved in
balanced-to-unbalanced circuits.
117 for amplifiers with unbalanced input involved in
unbalanced-to-balanced circuits.
122 for push-pull amplifiers with significant input
coupling.
143 for amplifiers having thermally responsive impedance
which may be in the input coupling.
144 for amplifiers with variable impedance controlled by
separate control path which may be in the input coupling.
147 for plural signal inputs.
157 appropriate subclasses for input coupling involved in
interstage coupling particularly subclasses 158+ and 160+.
See (3) Note under this subclass above.
192 for output coupling networks.
252 for semiconductor amplifiers with plural inputs.
275 and 301, for semiconductor amplifier devices having
balanced coupling.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 24 for passive
coupling networks for wave transmission generally.
338, Electrical Resistors, appropriate subclasses for the
structure of rheostats or resistors which may be used in
input coupling.
Subclass:
186
This subclass is indented under subclass 185. Subject matter
wherein the input signal is coupled to the cathode of a
vacuum tube amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
88 and 91+, for signal feedback to a cathode circuit,
particularly subclass 89 for cathode-cathode coupling between
adjacent stages.
119 for push-pull amplifiers involving coupling to the
cathode.
156 involving coupling directly between cathode and grid.
158 for interstage coupling to the cathode.
250 for subject matter including semiconductor device input
coupling to emitter, which may be the dual or analogue of an
input coupling circuit to the cathode electrode of a vacuum
tube amplifying device.
Subclass:
187
This subclass is indented under subclass 186. Subject matter
wherein the input coupling network has a D.C.. conductive
path from the source of signal energy to the cathode input
electrode of the amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
159 for D.C.. interstage coupling to the cathode of a vacuum
tube amplifying device.
Subclass:
188
This subclass is indented under subclass 185. Subject matter
in which the input circuit includes a transformer which
couples the signal energy from the signal source to the
amplifier device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
120 for interstage coupling between push-pull stages which
may involve transformer coupling.
122 for input coupling for push-pull amplifiers which may
involve transformer coupling.
154 for transformer coupling which may be involved in a
cascaded amplifier with different interstage couplings.
165 involving interstage transformer coupling.
195 for output transformer coupling.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 177 for passive
wave transmission transformer coupling circuits generally.
Subclass:
189
This subclass is indented under subclass 188. Subject matter
wherein additional impedance which may be capacitive,
inductive, or resistive is included in either the primary or
secondary winding circuit of the input coupling transformer.
SEE OR SEARCH THIS CLASS, SUBCLASS:
167 for interstage transformer coupling, with additional
impedance in the primary or secondary winding circuit.
195 for output transformer coupling including additional
impedance in the primary or secondary winding of the
transformer coupling network.
Subclass:
190
This subclass is indented under subclass 188. Subject matter
involving the structure of the transformer in the input
coupling circuit.
SEE OR SEARCH THIS CLASS, SUBCLASS:
65 for structure of amplifier system elements other than
that of the transformer.
170 for interstage transformer coupling with shielding.
171 for interstage transformer structure.
197 for structure of the transformer in the output
coupling.
SEE OR SEARCH CLASS:
336, Inductor Devices, appropriate subclasses for transformer
structure, per se.
Subclass:
191
This subclass is indented under subclass 185. Subject matter
wherein the input coupling circuit has a D.C.. conductive
path from the signal input source to the signal input
electrode of the amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for periodic switching for input-output comparison
including drift corrected D.C.. amplifiers.
10 for modulator-demodulator amplifiers for amplifying D.C..
signals.
53 for amplifiers having distributed parameter coupling
means which may have a D.C.. conductive path.
125 for plural amplifier channels involving a D.C.. and an
A.C. amplifier channel.
159 for interstage D.C.. coupling to cathode.
161 for interstage D.C.. coupling to screen grid or
electrode other than control grid or cathode.
163 for D.C.. interstage coupling from grid or between grid
and anode.
173 for D.C.. interstage coupling from cathode.
181 for D.C.. interstage coupling.
187 for cathode input D.C.. coupling.
194 for D.C.. coupling from cathode.
198 for D.C.. output coupling.
Subclass:
192
This subclass is indented under the class definition.
Subject matter involving significant detail or distinctive
characteristics of the electrical circuit coupling the output
signal from the amplifying device to a load for utilizing
such signal; or involving electrical characteristics or
vacuum tube parameters such as output impedance of the
amplifying device or impedance of the load involved in such
coupling.
(1) Note. Where the load is claimed, even broadly, or by
name only as a specific electrical art device, as for
example, as a loudspeaker, classification is not in this
class, but with the load art device claimed. Where
characteristics of the load device are claimed, which are
peculiar to the disclosed electrical art device or to a
specific type of electrical art device, classification is
with the load art device established in the claim.
(2) Note. Subject matter wherein general electrical
characteristics of the load are claimed, as for example, "a
load having a variable impedance", is classified in this or
indented subclasses.
(3) Note. Subject matter disclosing an interstage coupling
and where only the output coupling of a preceding stage is
claimed, is not classified in this and indented subclasses,
although the coupling is claimed to establish an output
coupling or claimed as an output coupling.
(4) Note. Subject matter wherein an amplifier combined with
an oscillator as load for the amplifier are classified with
amplifiers when the oscillator is claimed by name only. Where
specific details of the oscillator are claimed classification
is elsewhere.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for distributed parameter type output coupling.
65 for output coupling involving structure of any of the
output network circuit elements.
73 for plural outputs from series energized tubes.
105 for output coupling involving feedback from an impedance
in series with the output load.
108 for output coupling including a potentiometer therein
common to the signal and feedback paths.
116 for unbalanced output coupling in amplifiers having
balanced-unbalanced coupling.
117 for balanced output coupling in amplifiers having
unbalanced-balanced coupling.
122 for output coupling from a push-pull amplifier.
143 for thermally responsive impedance which may be in the
output coupling.
144 for variable impedance which may be in the output
coupling.
157 for interstage coupling involving coupling from the
output of an amplifier device particularly subclasses 162+
for output coupling from grid or between grid and anode,
subclass 168 for transformer coupling from cathode, 172+ for
other interstage coupling from the cathode.
185 for input coupling networks for amplifiers.
252 for semiconductor amplifiers having plural outputs.
275 and 301, for semiconductor amplifiers having either
balanced or unbalanced output.
SEE OR SEARCH CLASS:
331, Oscillators, where specific details of the oscillator
are claimed.
333, Wave Transmission Lines and Networks, 24 for passive
coupling networks for wave transmission in general.
Subclass:
193
This subclass is indented under subclass 192. Subject
matter, wherein the output signal is coupled from the cathode
electrode of a vacuum tube amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for series energized vacuum tube amplifiers which may
have the output coupled from the cathode of a vacuum tube
amplifying device.
88 and 91, for signal feedback coupled from the cathode
particularly subclass 89 for cathode-cathode coupling of
adjacent stages.
117 for unbalanced-to-balanced coupling including phase
splitters having cathode coupled output.
119 for push-pull amplifiers involving coupling from the
cathode.
153 for cascaded amplifiers having plural interstage
couplings of different characteristics.
156 for bootstrap coupling.
168 for transformer interstage coupling from the cathode.
172 for interstage coupling from the cathode.
250 for semiconductor device emitter follower circuits,
analogous to cathode follower circuits.
293 and 296, for series energized cascaded semiconductor
amplifier devices which may have the output coupled from an
emitter electrode of a transistor.
Subclass:
194
This subclass is indented under subclass 193. Subject matter
in which the output coupling network has a D.C.. conductive
path from the cathode to the load.
SEE OR SEARCH THIS CLASS, SUBCLASS:
173 for D.C.. coupling from the cathode involved in
interstage coupling.
Subclass:
195
This subclass is indented under subclass 192. Subject matter
in which the output circuit network includes a transformer
for coupling the signal from the amplifier device to the
load.
SEE OR SEARCH THIS CLASS, SUBCLASS:
120 and 122, for push-pull amplifiers which may involve
transformer output coupling.
154 for transformer coupling involved in plural diverse
stages of a cascaded amplifier.
165 involving interstage transformer coupling.
188 for input transformer coupling.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, 177 for wave
transmission transformer coupling circuits in general.
334, Tuners, 59 and 61+ for tuners having a transformer in
the resonant circuit.
Subclass:
196
This subclass is indented under subclass 195. Subject matter
where additional impedance which may be capacitive,
inductive, or resistive is included in the primary or
secondary winding circuit of the output coupling
transformer.
SEE OR SEARCH THIS CLASS, SUBCLASS:
167 for interstage transformer coupling with additional
impedance in the primary or secondary winding circuit.
189 for input transformer coupling with additional impedance
connected in the primary or secondary winding circuit.
Subclass:
197
This subclass is indented under subclass 195. Subject matter
involving the structure of the transformer in the output
coupling circuit.
SEE OR SEARCH THIS CLASS, SUBCLASS:
65 for structure of amplifier system elements other than
that of the transformer.
170 for interstage transformer coupling with shielding.
171 for interstage transformer structure.
190 for input transformer structure.
SEE OR SEARCH CLASS:
336, Inductor Devices, appropriate subclasses for transformer
structure, per se.
Subclass:
198
This subclass is indented under subclass 192. Subject matter
wherein the output coupling network has a D.C.. conductive
path from the output electrode of the amplifying device to
the load.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for periodic switching for input-output comparison
including drift corrected D.C. amplifiers.
10 for modulator-demodulator amplifiers for amplifying D.C..
signals.
53 for amplifiers having distributed parameter coupling
means which may have a D.C.. conductive path.
125 for plural amplifier channels involving a D.C.. and an
A.C. amplifier channel.
159 for interstage D.C.. coupling to cathode.
161 for interstage D.C.. coupling to screen grid or
electrode other than control grid or cathode.
163 for D.C.. interstage coupling from grid or between grid
and anode.
173 for D.C.. interstage coupling from cathode.
181 for D.C.. interstage coupling.
187 for cathode input D.C.. coupling.
191 for D.C.. input coupling.
194 for D.C.. coupling from cathode.
Subclass:
199
This subclass is indented under the class definition.
Subject matter in which the "source of electrical energy"
controlled by the signal input; or biasing means applied to
the "amplifying device", or the means to apply such energy or
bias, such as the circuits through which such source or bias
is applied; or means for isolating such source or biasing
means from the signal path or other amplifier circuits (by
filters, isolating resistors, or other means), is
significantly claimed, and which subject matter is not
provided for in any of the previous subclasses.
(1) Note. Merely claiming power supply source or biasing
means by name only or broadly without significant detail or
distinctive characteristics is insufficient for
classification in this and indented subclasses.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for maser type amplifying devices.
5 for solid element wave propagating amplifying devices.
6 for Hall effect type means.
7 for capacitive amplifying devices.
8 for saturable reactor type amplifying devices.
41 for gas or vapor tube amplifying devices.
42 for secondary electron emission tube amplifying device.
43 for traveling wave type tube.
44 for electron beam tube amplifying device.
47 for magnetically influenced discharge devices, (e.g.,
magnetrons).
49 for vacuum tube having distributed parameter impedance
characteristics.
58 for rotating dynamoelectric amplifying devices.
60 for magnetostrictive type amplifying devices.
61 for restrictive and magnetoresistive type amplifying
devices.
63 for significant power supply or biasing means combined
with an amplifying device and magnetic means which controls
the energy of said power supply or biasing means, or when a
magnetic means is involved in some other manner in the
structure of an amplifying device combined with significant
power supply or biasing means.
64 for space charge grid tubes biased to operate as such.
70 for series energized vacuum tube amplifiers and 18 for
series energized semiconductor amplifiers.
113 for polyphase power supply.
114 for unrectified A.C. power supply.
123 for amplifiers including a push-pull stage having
significant bias or power supply means.
127 for amplifiers with means to control the bias or power
supply voltage.
142 for cathode self-biasing circuits.
149 for hum elimination by introduction of the hum component
in the signal path in opposed phase.
296 and 297, for semi-conductor type amplifying devices when
combined with significant power supply or bias means or
involving related circuitry.
SEE OR SEARCH CLASS:
307, Electrical Transmission or Interconnection Systems, 149
for miscellaneous "power pack'' systems.
315, Electric Lamp and Discharge Devices: Systems, 91 for
cathode or cathode heater including anode supply circuit but
not including any grid biasing circuit.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 530 for miscellaneous circuits
combined with power supply or bias means.
329, Demodulators, appropriate subclasses for demodulators
with particular power supply.
359, Optics: Systems (Including Communication) and Elements,
333 for laser amplifiers.
Subclass:
200
This subclass is indented under subclass 199. Subject matter
where the power supply or bias means is for an amplifier
comprising two or more stages of amplification.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for plural diverse type amplifying devices which may
involve power supply or bias means.
88 92, and 98+, for cascaded signal feedback amplifiers which
may involve power supply or bias means.
123 for push-pull amplifiers, which may be cascaded, having
significant bias or power supply means.
124 for plural amplifier channels which may involve cascaded
amplifiers having significant power or bias supply means.
133 for different bias controls for different stages of a
cascaded amplifier.
150 for cascaded amplifiers with different characteristics
which may be different bias means or voltages.
152 for cascaded amplifiers, differently coupled between
stages, which may involve circuitry for the bias or power
supply means also.
157 for amplifiers with interstage coupling circuits which
may involve circuitry for the bias or power supply means
also.
296 for plural stage semiconductor amplifiers involving bias
or power supply circuitry.
Subclass:
201
This subclass is indented under subclass 200. Subject matter
where the filamentary cathodes of at least one vacuum tube
amplifying device of the plural stage amplifier derives its
electrical heating supply either from the anode or anode
power supply of one vacuum tube amplifying device stage of
the plural stage amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
115 for amplifiers having unrectified A.C. power supplied to
a filamentary cathode (directly heated type).
205 for similar subject matter for a filamentary cathode
also involving power supply or bias means for an input
electrode.
206 for power supply or bias means applied to a filamentary
cathode (directly heated type), generally.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems, 94 for
power supply or power supply circuit for cathode filament or
cathode heater circuit with or without anode supply but not
including grid biasing supply.
Subclass:
202
This subclass is indented under subclass 199. Subject matter
wherein the "source of electrical energy", biasing means, the
circuit or means for supplying such electrical energy or bias
voltage, or isolating means for such source or bias means
supplies the anode of a vacuum tube amplifying device or
isolates such supply for the anode from other parts of the
amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
70 for series energized amplifiers.
128 for control of bias or power supply voltage with control
means in anode or screen grid circuit.
157 185+ and 192+, appropriate subclasses thereunder for
impedances from the power source to anode involved in
interstage, input, and output coupling respectively.
293 for series energized semiconductor amplifying devices.
Subclass:
203
This subclass is indented under subclass 202. Subject matter
where additional bias supply or isolating means are furnished
for an input electrode of an amplifying device.
(1) Note. Input electrode refers to any electrode to which
the electrical signal input is applied, usually the control
grid physically next to the cathode, and the cathode which
is, usually, also common to the input and output circuits of
the amplifier, the anode being an output electrode.
(2) Note. Cathode self-biasing circuits where the bias is
established by the flow of plate current through the cathode
impedance are not classified herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
142 for cathode self-biasing circuits where the bias is
established by the flow of plate current through the cathode
impedance.
Subclass:
204
This subclass is indented under subclass 199. Subject matter
wherein the bias supply or isolating means is furnished to or
for an input electrode of a vacuum tube amplifying device.
(1) Note. Input electrode refers to any electrode to which
the electrical signal input is applied, usually the control
grid physically next to the cathode and the cathode which is
usually, also common to the input and output circuits of the
amplifier, the anode being an output electrode. In grounded
grid amplifiers the relationship of cathode and anode as
described above is, of course, usually reversed.
(2) Note. Cathode self-biasing circuits where the bias is
established by the flow of plate current through the cathode
impedance are not classified herein.
SEE OR SEARCH THIS CLASS, SUBCLASS:
142 for cathode self-biasing circuits where the bias is
established by the flow of plate current through the cathode
impedance.
157 185+ and 192+, for impedances in the input electrode bias
circuit involved in interstage, input, or output coupling,
respectively.
Subclass:
205
This subclass is indented under subclass 204. Subject matter
wherein power supply, bias means or isolating means are
supplied to the filamentary cathode of the vacuum tube
amplifying device, as input electrode; and/or as cathode
heating electrical current supply to the directly heated
filamentary cathode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
115 for amplifiers having unrectified A.C. power supplied to
a filamentary cathode.
127 for control of emission of a cathode electrode.
201 for power supply bias means for cathode filaments in a
plural stage amplifier heated by the anode current or by
current from the anode supply source.
206 for power supply for a filamentary cathode generally.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems, 94 for
power supply or power supply circuit for cathode filament or
cathode heater circuit with or without anode supply but not
including grid biasing supply.
Subclass:
206
This subclass is indented under subclass 199. Subject matter
which may include the heater current supply for a filamentary
cathode of a vacuum tube amplifying device not classified in
any preceding subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
115 for amplifiers having unrectified A.C. power supplied to
a filamentary cathode.
127 for control of emission of a cathode electrode.
201 for power supply bias means for cathode filaments in a
plural stage amplifier heated by the anode current or by
current from the anode supply source.
205 for similar subject matter for a filamentary cathode
also involving power supply or bias means for an input
electrode.
SEE OR SEARCH CLASS:
315, Electric Lamp and Discharge Devices: Systems, 94 for
power supply or power supply circuit for cathode filament or
cathode heater circuit with or without anode supply but not
including grid biasing supply.
Subclass:
207
This subclass is indented under the class definition.
Subject matter not provided for in any of the subclasses
above.
Subclass:
250
WITH SEMICONDUCTOR AMPLIFYING DEVICE (E.G., TRANSISTOR):
This subclass is indented under the class definition.
Subject matter in which the amplifying device is a
semiconductor.
(1) Note. Semiconductors are those materials which have a
specific resistance, for example, of the order of that of
germanium, silicon, selenium, etc.. Subject matter including
insulators which are in operation reduced to specific
resistance values of the aforesaid range, by alpha or
electron bombardment, heat or other means so they act in the
circuit, broadly, as semiconductors, are classified in this
or appropriate indented subclasses.
(2) Note. For specific types of amplifier devices in
amplifiers, which may include a semiconductor material, see
the pertinent subclass for the particular semiconductor
device involved in this class.
(3) Note. For vacuum tube amplifier device, amplifier
circuits similar or related to semiconductor amplifier device
circuits, see below the appropriate subclass and indented
subclasses for such circuit.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for combined plural diverse amplifying-type devices, where
one of the amplifying devices is of the semiconductor type.
4 for master-type amplifying devices wherein the master
excited substance is a semiconductor.
4.9 for parametric semiconductor amplifiers.
5 for solid element wave propagating amplifying devices
wherein the solid element is a semiconductor.
6 for Hall effect-type semiconductor amplifying devices
wherein the Hall effect material is a semiconductor.
7 for capacitive amplifying devices, some of which may have
semiconductor properties.
9 for amplifier systems with periodic switching input-output
comparison of signal which may have a semiconductor
amplifying device.
10 for modulator-demodulator amplifier systems which may
have semiconductor amplifier devices.
11 for amplifiers having D.C. reinsertion circuits which may
include a semiconductor amplifying device.
SEE OR SEARCH CLASS:
257, Active Solid-State Devices (e.g., Transistors,
Solid-State Diodes), appropriate subclasses integrated
circuit structure with active solid-state devices, especially
subclass 115, 123, and 157 through 161 for regenerative type
devices with amplification means, and subclasses 446 and 499+
for integrated circuit devices with electrically isolated
components.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for
miscellaneous nonlinear conductor device (e.g., transistor)
circuits. See search notes.
329, Demodulators, appropriate subclasses for demodulators
utilizing transistor elements.
361, Electricity: Electrical Systems and Devices, for
transistor circuits with electric relays or electromagnetic
loads.
438, Semiconductor Device Manufacturing: Process, appropriate
subclass for methods of making semiconductor electrical
devices.
Subclass:
251
Including class D amplifier:
This subclass is indented under subclass 250. Subject matter
including an amplifier which utilizes switching-mode
techniques.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 and 10, for amplifiers which may use switching amplifiers
as a subcircuit thereof.
207 for amplifiers using switching-mode techniques.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 365 for transistors used in a
switching mode.
Subclass:
252
Including differential amplifier:
This subclass is indented under subclass 250. Subject matter
including an amplifier having two similar input circuits so
connected that they respond to the difference between two
voltages or currents, but effectively suppress like voltages
or currents.
SEE OR SEARCH THIS CLASS, SUBCLASS:
69 for tube-type amplifiers functioning in a differential
mode.
Subclass:
253
Having field effect transistor:
This subclass is indented under subclass 252. Subject matter
wherein a field effect transistor (FET) is utilized in the
circuit with the differential amplifier.
(1) Note. A field effect transistor (FET) is a
semiconductor device in which the resistance between two
terminals, the source and drain, depends on a field produced
by a voltage applied to the third terminal, the gate.
(2) Note. The field may modulate a depletion region, as in
a junction FET, or it may cause a conductivity change in a
channel, as in a MOS-FET.
SEE OR SEARCH THIS CLASS, SUBCLASS:
264 for FET in combination with push-pull utilized in
complementary symmetry.
269 for FET in combination with push-pull amplifier.
277 for FET in other transistor amplifiers.
300 for FET in combined diverse-type circuit.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 581 for field-effect
transistors used in miscellaneous circuits.
Subclass:
254
Having gain control means:
This subclass is indented under subclass 252. Subject matter
including circuitry which controls the amplification of the
applied signal.
(1) Note. Gain is any increase in power when a signal is
transmitted from one point to another.
SEE OR SEARCH THIS CLASS, SUBCLASS:
278 for other semiconductor amplifiers with gain control.
SEE OR SEARCH CLASS:
348, Television, 645 for color television circuits having
gain control.
Subclass:
255
Having push-pull amplifier stage:
This subclass is indented under subclass 252. Subject matter
including an amplifier which has two identical signal
branches connected so as to operate in phase opposition and
with input and output connections, each balanced to ground.
SEE OR SEARCH THIS CLASS, SUBCLASS:
77 for push-pull amplifiers with feedback neutralization.
81 for push-pull amplifiers with feedback.
118 for vacuum tube amplifiers including a push-pull stage.
262 for push-pull amplifiers not in combination with
differential amplifiers.
Subclass:
256
Having temperature compensation means:
This subclass is indented under subclass 252. Subject matter
wherein temperature compensating means are utilized to
protect or stabilize the amplifying device from changes in
the ambient temperature.
(1) Note. Changes in the ambient temperature can change the
operating characteristics of the amplifier and thereby change
the output signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
266 for temperature compensation in complementary push-pull
amplifiers.
272 for temperature compensation in a push-pull amplifier.
289 for temperature compensation in other transistor
amplifiers.
Subclass:
257
Having current mirror amplifier:
This subclass is indented under subclass 252. Subject matter
wherein an amplifier having a gain which is substantially
independent of the individual common emitter forward current
gains of its component transistor, is utilized.
SEE OR SEARCH THIS CLASS, SUBCLASS:
288 for current mirror amplifier in other transistor
amplifiers.
Subclass:
258
Having common mode rejection circuit:
This subclass is indented under subclass 252. Subject matter
wherein means are utilized which ignore a signal that appears
simultaneously and in phase at both input terminals.
SEE OR SEARCH THIS CLASS, SUBCLASS:
69 for differential amplifiers which may include a common
mode rejection circuit.
Subclass:
259
Having D.C. feedback bias control for stabilization:
This subclass is indented under subclass 252. Subject matter
including a feedback circuit for direct currents for the
purpose of operating point stabilization.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching for input-output
comparison including those having feedback circuits for drift
correction, etc..
270 for D.C. feedback in push-pull complementary symmetry
amplifiers.
290 for D.C. feedback in other transistor amplifiers.
Subclass:
260
Having signal feedback means:
This subclass is indented under subclass 252. Subject matter
wherein a portion of the electrical signal output energy is
applied to the input of the amplifier.
(1) Note. There is a shared impedance for the input and
output circuits involved.
(2) Note. The amplifier in this subclass may be any stage
or group of stages of a cascaded amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching input-output
comparison including those with feedback circuits.
75 appropriate subclasses for vacuum tube signal feedback
amplifiers.
265 for signal feedback in complementary push-pull
amplifiers.
271 for signal feedback in push-pull amplifier.
282 for signal feedback in gain control circuit.
291 for feedback in other transistor amplifiers.
Subclass:
261
Having particular biasing arrangement:
This subclass is indented under subclass 252. Subject matter
with specific details or distinctive characteristics of the
biasing means applied to the amplifying device.
(1) Note. Merely claiming biasing means or bias filter by
name only, or broadly without significant detail or
distinctive characteristics, is insufficient for
classification in this subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 for particular biasing in other amplifiers.
267 for particular biasing in combination with complementary
symmetry.
273 for particular biasing in combination with a push-pull
amplifier.
285 for particular biasing in gain control means.
296 for particular biasing in other transistor amplifiers.
Subclass:
262
Including push-pull amplifier:
This subclass is indented under subclass 250. Subject matter
including at least one push-pull amplifier.
(1) Note. See the Glossary in this class for the definition
of "Push-Pull Amplifier".
SEE OR SEARCH THIS CLASS, SUBCLASS:
77 for push-pull amplifiers with feedback neutralization.
81 for push-pull amplifiers with feedback.
118 for vacuum tube amplifiers including a push-pull stage.
255 for push-pull amplifiers in combination with
differential amplifiers.
Subclass:
263
Having complementary symmetry:
This subclass is indented under subclass 262. Subject matter
wherein semiconductor devices of opposite conductivity are
utilized.
(1) Note. Complementary symmetry is an arrangement of NPN
and PNP transistors that provide push-pull operation from one
input signal.
(2) Note. There are two complementary types of conductivity
in semiconductors: The N-type where conduction is largely by
electrons; and the P-type where conduction appears to be
largely carried by positive charges (i.e., holes). In
junction transistors which consist of zones of more than one
conductivity type of semiconductor material, the conductivity
is determined by the control zone so that the PNP-type
junction transistor is equivalent to an N-type semiconductor
body or an N-type point contact semiconductor device and an
NPN junction type similarly equivalent to a P-type of
semiconductor device of a single conductivity type of
material.
Subclass:
264
And field effect transistor:
This subclass is indented under subclass 263. Subject matter
wherein a field effect transistor (FET) is utilized in the
circuit.
(1) Note. A field effect transistor (FET) is a
semiconductor device in which the resistance between two
terminals, the source and drain, depends on a field produced
by a voltage applied to the third terminal, the gate.
(2) Note. The field may modulate a depletion region, as in
a junction FET, or it may cause a conductivity change in a
channel, as in a MOS-FET.
SEE OR SEARCH THIS CLASS, SUBCLASS:
253 for FET in combination with differential amplifiers.
269 for FET in combination with push-pull amplifiers.
277 for field effect transistors in other transistor
amplifiers.
300 for field effect transistors in combined diverse-type
semiconductor devices.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 581 for miscellaneous
circuits using field-effect transistors.
Subclass:
265
And feedback means:
This subclass is indented under subclass 263. Subject matter
wherein a portion of the amplifier stage output signal is
returned to the input of the amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
260 for signal feedback in differential amplifiers.
271 for signal feedback in push-pull amplifiers.
282 for signal feedback in gain control circuits.
291 for signal feedback in other transistor amplifiers.
Subclass:
266
And temperature compensation:
This subclass is indented under subclass 263. Subject matter
wherein temperature compensating means are utilized to
protect or stabilize the amplifying device from changes in
the ambient temperature.
(1) Note. Changes in the ambient temperature can change the
operating characteristics of the amplifier and thereby change
the output signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
256 for temperature compensation in differential
amplifiers.
272 for temperature compensation in a push-pull amplifier.
289 for temperature compensation in other transistor
amplifiers.
Subclass:
267
And particular biasing arrangement:
This subclass is indented under subclass 263. Subject matter
with specific details or distinctive characteristics of the
biasing means applied to the amplifying device.
(1) Note. Merely claiming biasing means or bias filter by
name only, or broadly without significant detail or
distinctive characteristics, is insufficient for
classification in this subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 for particular biasing in general.
261 for particular biasing in combination with a
differential amplifier.
273 for particular biasing in combination with a push-pull
amplifier.
285 for particular biasing in gain control circuits.
296 for particular biasing not in combination in any of the
aforementioned.
Subclass:
268
To eliminate crossover distortion:
This subclass is indented under subclass 267. Subject matter
wherein distortion which occurs at the points of operation
where the input signals cross over the zero reference points
is eliminated.
SEE OR SEARCH THIS CLASS, SUBCLASS:
274 for means to eliminate crossover distortion in
noncomplementary, symmetry push-pull amplifiers.
Subclass:
269
Having field effect transistors:
This subclass is indented under subclass 262. Subject matter
wherein a field effect transistor (FET) is utilized in the
circuit.
(1) Note. A field effect transistor (FET) is a
semiconductor device in which the resistance between two
terminals, the source and drain, depends on a field produced
by a voltage applied to the third terminal, the gate.
(2) Note. The field may modulate a depletion region, as in
a junction FET, or it may cause a conductivity change in a
channel, as in a MOS-FET.
SEE OR SEARCH THIS CLASS, SUBCLASS:
253 for FET in combination with a differential amplifier.
264 for FET in complementary symmetry in push-pull.
277 for FET in other transistor amplifiers.
300 for FET in combined diverse-type circuit.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 581 for miscellaneous
circuits using field-effect transistors.
Subclass:
270
Having D.C. feedback bias control for stabilization:
This subclass is indented under subclass 262. Subject matter
with a feedback circuit for direct currents, for the purpose
of operating point stabilization.
(1) Note. Included here are devices for compensating for
changes in temperature, aging, etc.., of the semiconductor
device, or devices which may include means such as bypass
capacitors to eliminate signal feedback.
(2) Note. This does not include a mere bypassed emitter
resistor unless D.C. derived therefrom is applied to another
electrode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching for input-output
comparison including those having feedback circuits for drift
correction, etc..
259 for D.C. feedback in combination with a differential
amplifier.
290 for D.C. feedback in other transistor amplifiers.
Subclass:
271
Having signal feedback means:
This subclass is indented under subclass 262. Subject matter
wherein a portion of the electrical signal output energy is
applied to the input of the amplifier.
(1) Note. There is a shared impedance for the input and
output circuits involved.
(2) Note. The amplifier of this subclass may be any stage
or group of stages of a cascaded amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching input-output
comparison including those with feedback circuits.
75 appropriate subclasses for vacuum tube signal feedback
amplifiers.
265 for feedback in complementary push-pull amplifiers.
282 for signal feedback in gain control circuits.
291 for feedback in other transistor amplifiers.
Subclass:
272
Having temperature compensating means:
This subclass is indented under subclass 262. Subject matter
wherein temperature compensating circuits or devices are
utilized to protect or stabilize the semiconductor amplifying
devices from changes in the ambient temperature.
(1) Note. Changes in the ambient temperature of a circuit's
environment can change the operating characteristics of the
semiconductor amplifying device and thereby change the output
signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
256 for temperature compensation in a differential
amplifier.
266 for temperature compensation in complementary push-pull
amplifiers.
289 for temperature compensation in other transistor
amplifiers.
Subclass:
273
Having particular biasing arrangement:
This subclass is indented under subclass 262. Subject matter
with specific details or distinctive characteristics of the
biasing means applied to the amplifying device.
(1) Note. Merely claiming biasing means or bias filter by
name only, or broadly without significant details or
distinctive characteristics, is insufficient for
classification in this subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 for particular biasing in general.
261 for particular biasing in combination with a
differential amplifier.
267 for particular biasing in combination with complementary
symmetry.
285 for particular biasing in gain control circuits.
296 for particular biasing in other transistor amplifiers.
Subclass:
274
To eliminate crossover distortion:
This subclass is indented under subclass 273. Subject matter
wherein distortion which occurs at the points of operation
where the input signals cross over the zero reference points
is eliminated.
SEE OR SEARCH THIS CLASS, SUBCLASS:
268 for means to eliminate crossover distortion in
complementary symmetry.
Subclass:
275
Having balanced to unbalanced circuitry and vice versa:
This subclass is indented under subclass 262. Subject matter
wherein one of the signal input means or signal output means
is coupled to or from the semiconductor amplifier by a
balanced circuit, the other signal coupling means coupled to
or from the semiconductor amplifier balanced circuit.
(1) Note. For the definition of a "Balanced Circuit", see
the class definition, Glossary.
SEE OR SEARCH THIS CLASS, SUBCLASS:
301 for balanced to unbalanced circuits and vice versa in
other transistor amplifiers.
Subclass:
276
Having transformer:
This subclass is indented under subclass 262. Subject matter
wherein a transformer is included in the circuit.
(1) Note. The transformer can be in the input, output,
interstage, or any combination of the aforementioned.
Subclass:
277
Including field effect transistor:
This subclass is indented under subclass 250. Subject matter
wherein a field effect transistor (FET) is utilized in the
amplifier circuit.
(1) Note. A field effect transistor (FET) is a
semiconductor device in which the resistance between two
terminals, the source and drain, depends on a field produced
by a voltage applied to the third terminal, the gate.
(2) Note. The field may modulate a depletion region, as in
a junction FET, or it may cause a conductivity change in a
channel, as in a MOS-FET.
SEE OR SEARCH THIS CLASS, SUBCLASS:
253 for FET in differential amplifiers.
264 for FET in combination with push-pull utilized in
complementary symmetry.
269 for FET in combination with push-pull amplifiers.
300 for FET in combined verse-type circuit.
Subclass:
278
Including gain control means:
This subclass is indented under subclass 250. Subject matter
including circuitry which controls the amplification of the
applied signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
52 for amplifiers having pilot frequency control means.
96 for feedback amplifiers combined with control of bias
voltage of a signal amplifier.
123 for push-pull amplifiers having significant power or
bias supply circuits including those with bias control
means.
127 for amplifiers with control of power supply or bias
voltage.
143 for amplifiers having a thermally responsive impedance.
144 for amplifiers having a variable impedance in the signal
path varied by a separate control path.
155 for amplifiers having unicontrol of coupling or
associated circuits including unicontrol of signal input or
output potentiometers, etc..
157 185+ and 192+, for interstage input or output coupling,
respectively, including variable impedance means in such
coupling.
254 for gain control means in combination with a
differential amplifier.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, particularly
subclass 14, 16, and 17.1 for combined amplifier compressor
and expander means, pilot controlled means, and automatically
controlled systems, respectively; subclasses 24+ for coupling
networks which may include signal amplitude control means;
subclasses 213+ for negative resistance and/or reactance
networks of the active element type; and subclass 81 for
attenuators.
455, Telecommunications, 232.1 for volume control,
especially subclasses 234.1+ for automatic volume control.
Subclass:
279
And significant control voltage developing means:
This subclass is indented under subclass 278. Subject matter
including specific details or distinctive characteristics of
the gain control developing means.
SEE OR SEARCH THIS CLASS, SUBCLASS:
127 143 and 144+, for other amplifiers having gain control
systems which may have significant control voltage developing
means.
SEE OR SEARCH CLASS:
455, Telecommunications, 232.1 for receivers which may have
significant control voltage developing means as part of a
gain control system.
Subclass:
280
With delay means:
This subclass is indented under subclass 279. Subject matter
including circuit means which impart to the control voltage,
a minimum level at which the control voltage developing means
begins to function.
SEE OR SEARCH THIS CLASS, SUBCLASS:
127 143 and 144+, for gain-controlled amplifiers which may
have delay means.
SEE OR SEARCH CLASS:
455, Telecommunications, 242.1 for gain-controlled receivers
which may have delay means.
Subclass:
281
With time constant means:
This subclass is indented under subclass 279. Subject matter
including a circuit for filtering the control voltage, and
wherein specific details or distinctive characteristics of
such circuit are claimed.
SEE OR SEARCH THIS CLASS, SUBCLASS:
127 143 and 144+, for amplifiers which may include
time-constant means in the control voltage path thereof.
SEE OR SEARCH CLASS:
455, Telecommunications, 239.1 for gain-controlled receivers
which may include time-constant means in the control voltage
path thereof.
Subclass:
282
Having feedback means acting as variable impedance:
This subclass is indented under subclass 278. Subject matter
including a feedback means acting as a variable impedance to
control the gain of the amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
86 for amplifiers having variable impedance in feedback path
varied by separate control path.
Subclass:
283
Having emitter degeneration:
This subclass is indented under subclass 282. Subject matter
including a feedback means acting as a variable impedance in
the common electrode of the amplifier to control the gain of
the amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
95 for amplifiers having nonlinear impedance means in the
cathode impedance feedback path.
Subclass:
284
Having attenuation means in signal transmission path:
This subclass is indented under subclass 278. Subject matter
having attenuation means in signal transmission path that
controls the gain of the amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
52 for amplifiers having pilot frequency control means.
143 for amplifiers having thermally responsive means.
144 for amplifiers having variable impedance for signal
channel controlled by separate control path.
SEE OR SEARCH CLASS:
455, Telecommunications, subclass 249.1 for gain-controlled
receiver having variable impedance in the control circuit.
Subclass:
285
Having particular biasing means:
This subclass is indented under subclass 278. Subject matter
having specific details or distinctive characteristics of a
biasing means for applying a biasing voltage to the
amplifying device.
(1) Note. Merely claiming biasing means or bias filter by
name only, or broadly without significant detail or
distinctive characteristics, is insufficient for
classification in this subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
127 for amplifiers with control of power supply or bias
voltage.
199 for particular biasing in other amplifiers.
261 for particular biasing in differential amplifiers.
267 for particular biasing in combination with complementary
symmetry.
273 for particular biasing in combination with a push-pull
amplifier.
285 for particular biasing in gain control circuits.
296 for particular biasing in other transistor amplifiers.
Subclass:
286
Including distributed parameter-type coupling:
This subclass is indented under subclass 250. Subject matter
including coupling means which has both distributive
capacitance and distributive inductance at high frequencies.
SEE OR SEARCH THIS CLASS, SUBCLASS:
53 for amplifiers having distributed-type coupling.
SEE OR SEARCH CLASS:
331, Oscillators, 56 for oscillators having distributed
parameter resonator.
333, Wave Transmission Lines and Networks, 219 for
distributed parameter resonator, and subclasses 236+ for long
lines having distributed parameters.
Subclass:
287
Of diode type:
This subclass is indented under subclass 286. Subject matter
including amplifying means of the diode type.
SEE OR SEARCH CLASS:
331, Oscillators, subclass 107 for diode-type oscillators.
Subclass:
288
Including current mirror amplifier:
This subclass is indented under subclass 250. Subject matter
wherein an amplifier having a gain which is substantially
independent of the individual common emitter forward current
gains of its component transistor is utilized.
SEE OR SEARCH THIS CLASS, SUBCLASS:
257 for current mirror amplifiers in combination with
differential amplifiers.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 530 for miscellaneous transistor
circuits used for power supply or bias regulation.
Subclass:
289
Including temperature compensation means:
This subclass is indented under subclass 250. Subject matter
wherein temperature compensating means are utilized to
protect or stabilize the amplifying device from changes in
the ambient temperature.
(1) Note. Changes in the ambient temperature can change the
operating characteristics of the amplifier and thereby change
the output signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
256 for temperature compensation in a differential
amplifier.
266 for temperature compensation in complementary push-pull
amplifiers.
272 for temperature compensation in a push-pull amplifier.
Subclass:
290
Including D.C. feedback bias control for stabilization:
This subclass is indented under subclass 250. Subject matter
with feedback circuit for direct currents, for the purpose of
operating point stabilization as compensating for changes in
temperature, aging, etc.., of the semiconductor device, or
devices, which may include means such as bypass capacitors to
eliminate signal feedback.
(1) Note. This does not include a mere bypass emitter
resistor unless D.C. derived therefrom is applied to another
electrode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching for input-output
comparison including those having feedback circuits for drift
correction, etc..
97 for amplifiers including D.C. path for signal feedback.
259 for D.C. feedback in differential amplifiers.
270 for D.C. feedback in push-pull complementary symmetry
amplifiers.
Subclass:
291
Including signal feedback means:
This subclass is indented under subclass 250. Subject matter
wherein a portion of the electrical signal output energy is
applied to the input of the amplifier.
(1) Note. There is a shared impedance for the input and
output circuits involved.
(2) Note. The amplifier of this subclass may be any stage
or group of stages of a cascaded amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
9 for amplifiers with periodic switching input-output
comparison including those with feedback circuits.
75 appropriate subclasses for vacuum tube signal feedback
amplifiers.
260 for signal feedback in differential amplifiers.
265 for feedback in complementary push-pull amplifiers.
271 for signal feedback in push-pull amplifiers.
282 for signal feedback in gain control circuits.
Subclass:
292
Having compensation for interelectrode impedance:
This subclass is indented under subclass 291. Subject matter
wherein signal feedback means are provided for, compensating
for, or nullifying the undesirable feedback caused by any of
the internal interelectrode impedances of the semiconductor
amplifying device.
SEE OR SEARCH THIS CLASS, SUBCLASS:
76 for neutralization through compensation by signal
feedback of the effects of interelectrode impedance in vacuum
tube amplifiers.
Subclass:
293
Having negative feedback:
This subclass is indented under subclass 291. Subject matter
wherein the signal feedback which is superimposed on the
input signal has at least one component thereof opposite in
phase to the input signal.
SEE OR SEARCH THIS CLASS, SUBCLASS:
75 for signal feedback in other amplifiers.
Subclass:
294
Having frequency responsive means or phase shift means in the
feedback path:
This subclass is indented under subclass 291. Subject matter
having frequency-responsive means or phase-shift means in the
feedback path that causes corresponding changes in amplifier
gain.
SEE OR SEARCH THIS CLASS, SUBCLASS:
107 and 109, for amplifiers having frequency- or
phase-responsive means in the feed-back path.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 113 for miscellaneous frequency
control, subclasses 231+ for a phase shift of less than an
input signal period, subclasses 2+ for phase discriminating
without subsequent control, and subclasses 39+ for frequency
discriminating without subsequent control.
Subclass:
295
Including plural amplifier channels:
This subclass is indented under subclass 250. Subject matter
having more than one signal transmission path, each of which
contains an amplifier (e.g., plural inputs or plural
outputs).
SEE OR SEARCH THIS CLASS, SUBCLASS:
84 for signal feedback amplifiers having plural channels.
124 for amplifiers having plural amplifier channels.
147 for amplifiers having plural separate inputs.
148 for amplifiers having plural separate outputs.
Subclass:
296
Including particular biasing arrangement:
This subclass is indented under subclass 250. Subject matter
with specific details or distinctive characteristics of the
biasing means applied to the amplifying device.
(1) Note. Merely claiming biasing means or bias filter by
name only, or broadly without significant detail or
distinctive characteristics, is sufficient for classification
in this subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 for particular biasing in other amplifiers.
261 for particular biasing in differential amplifiers.
267 for particular biasing in combination with complementary
symmetry.
273 for particular biasing in combination with push-pull
amplifier.
285 for particular biasing in signal amplitude control.
Subclass:
297
Including particular power supply circuitry:
This subclass is indented under subclass 250. Subject matter
including specific details or distinctive characteristics of
the source of electrical energy applied to the semiconductor
amplifying device.
(1) Note. This includes means to apply such energy source,
the circuits through which such source is applied, and means
for isolating such source from the signal path or other
amplifier circuits.
(2) Note. Merely claiming power supply source by name only,
or broadly without significant detail or distinctive
characteristics, is insufficient for classification in this
subclass.
SEE OR SEARCH THIS CLASS, SUBCLASS:
199 for amplifiers generally involving bias or power supply.
See the search notes under subclass 199.
Subclass:
298
Including protection means:
This subclass is indented under subclass 250. Subject matter
including circuits or devices for protecting the amplifying
means.
SEE OR SEARCH THIS CLASS, SUBCLASS:
207 for amplifiers having protection circuitry.
Subclass:
299
Including combined diverse-type semiconductor device:
This subclass is indented under subclass 250. Subject matter
including plural semiconductor devices and at least one
semiconductor device which is different in its physical
characteristics or in materials, and which also amplifies the
signal.
(1) Note. Materials which may be a diode of the
nonamplifying type, or which may be an additional signal
carrier semiconductor amplifying device including an
amplifier not previously provided for in this schedule.
SEE OR SEARCH THIS CLASS, SUBCLASS:
94 and 110, for vacuum tube feedback amplifiers having
nonlinear impedance elements.
138 and 140, for amplifiers having a rectifier, which may be
a semiconductor diode, in a bias control circuit for the
input or gain control electrode.
143 for vacuum tube amplifiers having a thermally responsive
impedance.
144 for vacuum tube amplifiers having a separately
controlled variable impedance in the signal path, which may
be a semiconductor.
164 for vacuum tube amplifiers with a diode in the
interstage coupling which may be a semiconductor.
174 for a piezoelectric crystal or electromechanical
transducer broadly in the interstage coupling of a vacuum
tube amplifier.
183 for vacuum tube amplifiers having D.C. interstage
coupling with a nonlinear device therein.
Subclass:
300
Bipolar or unipolar (FET):
This subclass is indented under subclass 299. Subject matter
wherein the additional semiconductor device may be a bipolar
or unipolar transistor.
SEE OR SEARCH THIS CLASS, SUBCLASS:
253 for field effect transistor (FET) in combination with a
differential amplifier.
264 for FET in combination with complementary symmetry
push-pull amplifiers.
269 for FET in combination with other push-pull amplifiers.
277 for other field effect transistors.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, subclass 581 for miscellaneous FET
circuits.
Subclass:
301
Including balanced to unbalanced circuits and vice versa:
This subclass is indented under subclass 250. Subject matter
wherein one of the signal input means or signal output means
is coupled to or from the semiconductor amplifier by a
balanced circuit, the other signal coupling means coupled to
or from the semiconductor amplifier unbalanced circuit.
(1) Note. For the definition of a "Balanced Circuit", see
the Glossary in this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
275 for balanced to unbalanced circuits in push-pull
amplifiers.
Subclass:
302
Including frequency-responsive means in the signal
transmission path:
This subclass is indented under subclass 250. Subject matter
including frequency-responsive means in the signal
transmission path that causes corresponding changes in the
amplifier gain.
SEE OR SEARCH THIS CLASS, SUBCLASS:
157 185+ and 192+, for interstage input or output coupling,
respectively, including variable impedance means in such
coupling.
294 having frequency-responsive means or phase-shift means
in the feedback path.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 113 for miscellaneous frequency
control, subclasses 231+ for a phase shift of less than an
input signal period, subclasses 2+ for phase discriminating
without subsequent control, and subclasses 39+ for frequency
discriminating without subsequent control.
333, Wave Transmission Lines and Networks, 24 for frequency
or phase sensitive circuits in wave transmission lines and
networks.
Subclass:
303
Including an active device in the filter means:
This subclass is indented under subclass 302. Subject matter
including a transistor or active diode in the filter
network.
SEE OR SEARCH THIS CLASS, SUBCLASS:
107 109 and 294, for circuits having frequency-responsive
means or phase-shift means in the feedback path.
SEE OR SEARCH CLASS:
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 552 for miscellaneous circuits
suppressing an unwanted signal using an active filter.
333, Wave Transmission Lines and Networks, 24 for frequency
or phase sensitive circuits in wave transmission lines and
networks.
Subclass:
304
And equalizing means:
This subclass is indented under subclass 302. Subject matter
including a network connected to a line to correct or control
its transmission frequency characteristics.
SEE OR SEARCH CLASS:
333, Wave Transmission Lines and Networks, subclass 28 for
equalizers used in wave transmission lines and networks.
Subclass:
305
And tuning means:
This subclass is indented under subclass 302. Subject matter
including a manually adjustable frequency selecting means.
SEE OR SEARCH CLASS:
334, Tuners, appropriate subclasses for tuning circuits.
455, Telecommunications, 120 for transmitters having tuning
means; and subclasses 150.1+ for receivers having tuning
means.
Subclass:
306
And bandpass, broadband (e.g., wideband), or sidepass means:
This subclass is indented under subclass 302. Subject matter
including means which determines the range of the frequencies
of the applied signal that will be amplified.
SEE OR SEARCH CLASS:
455, Telecommunications, 188.1 for selectable band
receivers.
Subclass:
307
Integrated circuits:
This subclass is indented under subclass 250. Subclass
matter under having a combination of interconnected elements
inseparably associated on or within a continuous substrate.
(1) Note. If a claimed preferred embodiment of a patent
application includes details of means to apply a variable
electrical signal to an IC amplifying device, or details of
means to utilize the output of an IC amplifying device, that
application is properly classified in this subclass.
(2) Note. If, however, a claimed preferred embodiment of a
patent application is limited to details of an IC amplifying
device, without details of the input or output (utilization)
means, or the input or output (utilization) means are recited
in name only, then the application is properly classified
outside this class.
SEE OR SEARCH CLASS:
257, Active Solid-State Devices (e.g., Transistors,
Solid-State Diodes), appropriate subclasses for active
solid-state devices, especially subclass 115, 123, and
162-166 which are directed to devices involving
amplification. See the (2) Note above.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 564 for miscellaneous circuits which
are integrated.
Subclass:
308
Including atomic particle or radiant energy impinging on a
semiconductor:
This subclass is indented under subclass 250. Subject matter
in which the amplifying device semiconductor body is
subjected to radiant energy which may be in the form of
light, free (unrestrained) electromagnetic energy, gamma
rays, etc.., or atomic particle bombardment, such as alpha or
beta rays, etc..
(1) Note. If a claimed preferred embodiment of a patent
application includes details of means to apply a variable
electrical signal to an IC amplifying device, or details of
means to utilize the output of an IC amplifying device, that
application is properly classified elsewhere in this class
(330).
(2) Note. If, however, a claimed preferred embodiment of a
patent application is limited to details of an IC amplifying
device without details of the input or output (utilization)
means, or the input or output (utilization) means are recited
in name only, then the application is properly classified
elsewhere outside this class.
SEE OR SEARCH THIS CLASS, SUBCLASS:
4 for maser-type amplifying device which may involve a
semiconductor.
5 for solid element wave propagating amplifying devices
involving coupling or activation by electromagnetic wave
energy applied through wave energy constraining wave
propagating means, such as by wave guide.
307 for a claimed preferred embodiment of a patent
application includes details of means to apply a variable
electrical signal to an IC amplifying device, or details of
means to utilize the output of an IC amplifying device.
SEE OR SEARCH CLASS:
250, Radiant Energy, particularly 370.01 for methods and
apparatus using an invisible radiant energy-responsive
semiconductor device.
257, Active Solid-State Devices (e.g., Transistors,
Solid-State Diodes), appropriate subclasses for active
solid-state devices, especially subclass 115 which is
directed to light responsive devices involving amplification.
See (2) Note above.
313, Electric Lamp and Discharge Devices, appropriate
subclasses for discharge devices involving the structure of
ray energy generating, beaming and focusing, in the form of
electron beams, alpha ray, and X-ray emanations.
315, Electric Lamp and Discharge Devices: Systems, 1 for
cathode ray discharge devices involving circuits or special
circuit structure associated with the device.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, 509 for miscellaneous nonlinear
solid-state circuits subjected to some external effect.
359, Optics: Systems (Including Communication) and Elements,
333 for laser amplifiers.
Subclass:
309
Involving structure of three diverse function electrode
type:
This subclass is indented under subclass 250. Subject matter
wherein the semiconductor device is provided in three
diverse-type electrodes for coupling the signal energy input
and output, additional biasing or gain control, etc.., and
the application of the controlled electrical energy source in
which each electrode performs a distinct function.
(1) Note. If a claimed preferred embodiment of a patent
application includes details of means to apply a variable
electrical signal to an IC amplifying device, or details of
means to utilize the output of an IC amplifying device, that
application is properly classified elsewhere in this class.
(2) Note. If, however, a claimed preferred embodiment of a
patent application is limited to details of an IC amplifying
device without details of the input or output (utilization)
means, or the input or output (utilization) means are recited
in name only, then the application is properly classified
elsewhere outside this class.
SEE OR SEARCH CLASS:
257, Active Solid-State Devices (e.g., Transistors,
Solid-State Diodes), appropriate subclasses for active
solid-state devices, especially subclass 115, 123 and 162
through 166 which are directed to devices involving
amplification.
327, Miscellaneous Active Electrical Nonlinear Devices,
Circuits, and Systems, appropriate subclasses for similar
semiconductor devices in miscellaneous circuits.
Subclass:
310
Including plural stages cascaded:
This subclass is indented under subclass 250. Subject matter
including a plurality of stages of amplification, such that
the input signal for each stage, except the first, is the
output of the preceding stage.
SEE OR SEARCH THIS CLASS, SUBCLASS:
3 for plural diverse-type amplifying devices which may be
cascaded and which may include a semiconductor-type
amplifying device.
70 for series energized vacuum tube amplifiers which may be
cascaded.
88 92 and 98+, for cascaded amplifiers with signal feedback.
150 for cascaded vacuum tube amplifying devices of different
characteristics.
151 for cascaded vacuum tube amplifier devices with means to
bypass a stage.
152 for cascaded vacuum tube amplifier means differently
coupled between stages.
157 for interstage coupling between stages of amplifying
devices.
Subclass:
311
Having different configurations:
This subclass is indented under subclass 310. Subject matter
wherein at least one of the cascaded stages is of a different
configuration from at least one of the other cascaded
stages.
(1) Note. In a semiconductor amplifier having emitter,
base, and collector electrodes, input signal current flows
through two electrodes thereof, and output signal current
flows through two electrodes thereof, one of the electrodes
being common to both input and output circuits. Therefore,
in the three electrode semiconductor amplifier, there is a
common electrode, an input electrode and an output electrode.
By the configuration of a semi-conductor amplifier is meant
the arrangement of base, emitter, and collector electrodes
thereof, as the input, common, and output electrodes thereof.
The configuration is usually referred to as common base,
common emitter, or common collector configuration, but this
does not completely define the configuration which must have
at least one of the other semiconductor electrodes identified
by its function as input or output electrode.
SEE OR SEARCH THIS CLASS, SUBCLASS:
153 for cascaded vacuum tube amplifier devices with
differently coupled interstage circuits including at least
one cathode follower stage.
157 appropriate subclasses thereunder, for interstage
coupling to or from electrodes and as cathode, or from
electrodes such as cathode or screen grid not used in the
majority of vacuum tube amplifiers as input or output
electrode.
168 for vacuum tube interstage transformer coupling from the
cathode.
Information Products Division -- Contacts
Questions regarding this report should be directed to:
U.S. Patent and Trademark Office
Information Products Division
PK3- Suite 441
Washington, DC 20231
tel: (703) 306-2600
FAX: (703) 306-2737
email: oeip@uspto.gov
Last Modified: 6 October 2000