This is the generic class for pulse or digital communication
systems using electrical or electromagnetic signals. Such
communication includes transmitting an intelligence bearing signal
from one point to another in the form of discrete variations in
some parameter of the electrical or electromagnetic signal.
SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS
Telegraph and printing telegraph systems which include transmission
or reception of a carrier are classified in Class 375 except for
those systems specifically provided elsewhere, such as
a spark gap and a coherer. See References to Other Classes, below.
A carrier which is modulated by a continuously variable (analog) signal
is classified elsewhere (See References to Other Classes, below).
A device which is convertible from analog to pulse or digital may
have a time related parameter (e.g., pulse
width, or repetition rate) continuously variable
and be classified herein.
Light Wave Communication is classified elsewhere (See
References to Other Classes, below), regardless
of the type of modulation.
Duplexing or Multiplexing systems which utilize pulse or digital
information signals are classified elsewhere (See References
to Other Classes, below).
Code converters which may be utilized in a pulse or digital
communication system, are classified elsewhere (See
References to Other Classes, below).
Addressing of a particular pulse receiver is classified elsewhere (See
References to Other Classes, below).
The combination of the subject matter of this class (375) and
another art environment is generally classified with the other art
environment where that environment is significant by virtue of the
claimed relationship. For example: Error checking
systems; Electroacoustic geophysical systems; Dynamic
Magnetic Information Storage or Retrieval; Radar systems; Directive
systems; Telemetering systems; Television. See
References to Other Classes, below.
Significantly claimed pulse or digital communication handling
techniques in combination with the subject matter of 700, Data
Processing: Generic Control Systems or Specific Applications; 701, Data
Processing: Vehicles, Navigation, and
Relative Location; 702, Data Processing: Measuring, Calibrating, or
Testing; 703, Data Processing: Structural
Design, Modeling, Simulation, and Emulation; 704, Data
Processing: Speech Signal Processing, Linguistics, Language
Translation, and Audio Compression/Decompression; 705, Data
Processing: Financial, Business Practice, Management, or
Cost/Price Determination; 706, Data Processing: Artificial Intelligence; 707, Data
Processing: Database and File Management or Data Structures, or
Document Processing; 708, Electrical Computers: Arithmetic
Processing and Calculating; 709, Electrical Computers
and Digital Processing Systems: Multicomputer Data Transferring; 710, Electrical
Computers and Digital Data Processing Systems: Input/Output; 711, Electrical
Computers and Digital Processing Systems: Memory; 712, Electrical Computers
and Digital Processing Systems: Processing Architectures
and Instruction Processing (e.g., Processors); 713, Electrical
Computers and Digital Processing Systems: Support; 714, Error
Detection/Correction and Fault Detection/Recovery; 716, Data
Processing: Design and Analysis of Circuit or Semiconductor
Mask; or 717, Data Processing: Software
Development, Installation, and Management, are
classified in these external classes.
Remote control of a transmitter and/or receiver is
classified herein; however, the remote control
of a device external to a communication system is classified elsewhere. Remote
control of an external device by light wave communications is classified
elsewhere. See References to Other Classes, below.
Electrical circuits or devices which may use pulse or digital
handling techniques, but are not unique to communications, are
classified in the appropriate classes. For example: Pulse
characteristic discriminating, comparing or selecting. Pulse
responsive selective systems; Pulse demodulation, per
se; Pulse modulation converters to FM; Pulse modulation, per
se; Pulse generating oscillator; pulse counting
circuits and systems; Pulse counters and dividers; Pulse
shaping or converting; Digital comparator systems; Data
conversion. See References to Other Classes, below.
Digital television bandwidth reduction or expansion system
is classified in Class 375, subclasses 240.01-240.29; analog
television bandwidth reduction or expansion is classified with the
television art. See References to Other Classes, below.
Electricity: Measuring and Testing,
subclasses 76.12+ for analysis of complex waves; subclasses
76.39+ for measuring the repetition rate of pulses; and
subclasses 76.77+ for the phase comparison of
pulse voltages.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 1+ for pulse characteristic discriminating or selecting
and subclasses 100+ for miscellaneous pulse characteristic
control.
Communications: Electrical, subclasses 9.1 through 9.17 for addressing
of a particular pulse receiver;
subclasses 12.1 through 13.38for pulse responsive selective actuation systems, especially
subclasses 12.22-12.55 for remote control
of a device external to a communication system (e.g., model
airplane, etc.); subclass 146.2
for digital comparator systems; subclasses 870.01-870.44
for telemetering systems; and subclasses 870.18-870.24
for pulse modulated telemetering systems.
Coded Data Generation or Conversion, for code transmission, generation or conversion, including
code converters which may be utilized in a pulse or digital communication
system.
Television,
subclasses 471 and 472 and subclasses 488-494 for color
television systems utilizing pulse modulation and having receivers to
detect same, subclasses 384.1-440.1
for analog bandwidth reduction systems, and subclasses
725-738 for noncolor television receivers.
Static Information Storage and Retrieval,
subclasses 189.011+ and 230.01+ for a read/write or
addressing circuit which uses pulse signals in a static storage
system.
Communications, Electrical:
Acoustic Wave Systems and Devices, appropriate subclass for the communication of information
in the form of traveling stresses in an elastic medium;
subclasses 14+ for electroacoustic geophysical systems.
Optical Communications, various subclasses for light wave communication;
subclasses 106 through 114for remote control of an external device by light
wave communications.
Telecommunications, for a carrier which is modulated by a continuously
variable (analog) signal. however, simultaneous
transmission of independent analog and pulse or digital information
bearing signals is classified elsewhere.
Electrical Computers and Digital Data Processing
Systems: Multicomputer Data Transferring, appropriate subclassesfor data transferring among multiple computer
systems.
Electrical Computers and Digital Data Processing
Systems: Input/Output,
subclasses 1 through 74for Input/Output data processing involving
peripherals and digital data processing systems.
Error Detection/Correction and Fault
Detection/Recovery, appropriate subclasses for generic error checking
of digital devices.
SECTION IV - GLOSSARY
COMMUNICATIONS
The transmission of information from one point to another.
DIGITAL
Of or pertaining to the class of devices or circuits
in which the output varies in discrete steps (i.e., pulses
or "on-off" operation).
PULSE
A variation of a voltage or current normally having a constant
value. This variation is characterized by a rise and a
decay approaching infinitesimal duration.
This subclass is indented under the class definition. Subject matter utilizing a data modulated signal which has
its energy spread over a transmitted bandwidth which is much greater
than the bandwidth or rate of information being sent.
(1)
Note. Four general types of modulation that are
in the spread spectrum variety:
(a)
Modulation of a carrier by a data modulation signal whose
bit rate is much higher than the maximum possible repetition rate
of the pulses or discrete steps. Such systems are called "direct sequence" modulated
systems.
(b)
Carrier frequency shifting in discrete increments in a pattern
dictated by a code sequence. These are called "frequency
hoppers." The transmitter jumps from frequency to frequency
within some predetermined set; the order of frequency usage
is determined by a code sequence.
(c)
Pulse-FM or "chirp" modulation, in which
a carrier is swept over a wideband during a given pulse interval.
(d)
Ultra-wideband or ultra-short pulse modulation, in
which information is transmitted using extremely short-duration
signals.
(2)
Note. Wideband FM (or FSK) is
not classified here, see search this class, subclass
below.
(3)
Note. Closely akin to the frequency hoppers are
"time hopping" and "time-frequency hopping" systems,
whose chief distinguishing feature is that their time of transmission (usually
of low duty cycle and short duration) is governed by a
code sequence. In time-frequency hoppers it follows
that the code sequence determines both the transmitted frequency
and the time of transmission.
(4)
Note. Spread-spectrum multiple-access systems
are not classified here, see search class below.
(5)
Note. Chirp signal processing techniques (e.g., chirp
z-transforms) are not classified here unless they
are specifically used in spread-spectrum communications.
for systems transmitting a single message over multiple
channels, including orthogonal frequency division multiplexing
(also known as multi-carrier modulation or discrete
multi-tone modulation).
Communications: Directive Radio Wave
Systems and Devices, for subject matter relating to radar, navigation
and direction-finding systems using spread-spectrum
signaling.
Cryptography,
subclasses 200 through 251and 255-53, for subject matter involving
electric signal modification, including enciphering using
pseudo-random codes, or using plural shifting frequencies, et
al.
Telecommunications,
subclasses 42 through 45, 110-113 and subclasses 205-216, for
wideband FM, subclasses 422.1-466 and
subclasses 507-526, for subject matter relating
to zoned or cellular communication systems.
Data Processing: Vehicles, Navigation and
Relative Location,
subclasses 400 through 541for subject matter relating to navigation systems
using spread-spectrum signaling.
Electrical Computers: Arithmetic Processing
and Calculating,
subclasses 250 through 256,314, and 422-426, respectively, for
random number or sequence generation, matched filtering
and correlators implemented in the types of systems found in this class.
Chirp signal processing techniques per se are classified in subclasses
400-410.
This subclass is indented under subclass130. Subject matter wherein the spread spectrum signals are
made up of at least two different spread spectrum techniques.
(1)
Note. Examples of hybrid forms may include: (a) simultaneous
frequency hopping and direct sequence modulations, (b) simultaneous
time and frequency hopping, or (c) simultaneous time-hopping
and direct sequence modulations.
This subclass is indented under subclass 130. Subject matter including a system in which the wide band
signal is generated by jumping from one frequency to another over
multiple number of frequency choices.
This subclass is indented under subclass 132. Subject matter comprising at least two stations where
signals are transmitted and received between stations.
This subclass is indented under subclass 130. Subject matter including a system wherein waveforms are
transmitted at times which are selected from among a plurality of
time slots, with the selection of time slot being pseudo-random, if
desired.
This subclass is indented under subclass 130. Subject matter including a signal format in which a pulsed
carrier is transmitted and is varied continuously in frequency in
a known way during the transmission of a given pulse.
This subclass is indented under subclass 130. Subject matter including a form of modulation wherein
a code sequence is used to directly modulate a carrier, usually
by some form of phase-shift keying.
This subclass is indented under subclass 140. Subject matter comprising at least two stations where
signals are transmitted and received between stations.
This subclass is indented under subclass 141. Subject matter in which transmitted signals are recovered
using a structure or method that compares a transmitted spreading
code sequence with a local spreading code sequence, generally
by multiplicative means.
This subclass is indented under subclass 141. Subject matter in which transmitted signals are recovered
using a structure or method that is designed to pass only the specific
transmitted signal (i.e., spreading
code), that is matched to the spreading code used
to transmit the signal.
This subclass is indented under subclass 141. Subject matter in which transmitted signals are recovered
using a structure or method that either recovers multiple simultaneously-transmitted
signals or recovers a transmitted signal and rejects spurious signals.
This subclass is indented under subclass 141. Subject matter in which methods, involving the transmission
of specific types of patterns or waveforms, are used to
insure that proper spreading sequence timing is used at the receiver.
This subclass is indented under subclass 147. Subject matter in which transmitted signals are recovered
using a structure or method that either recovers multiple simultaneously-transmitted
signals or recovers a transmitted signal and rejects spurious signals.
This subclass is indented under subclass 147. Subject matter in which transmitted signals are recovered
using a structure or method that compares a transmitted spreading
code sequence with a local spreading code sequence, generally
by multiplicative means.
This subclass is indented under subclass 150. Subject matter in which the receiver is implemented using
at least one surface acoustic wave or charge-transfer (e.g., CCD) structure.
This subclass is indented under subclass 147. Subject matter in which transmitted signals are recovered
using a structure or method that is designed to pass only the specific
transmitted signal (i.e., spreading
code), that is, it is a matched to the
spreading code used to transmit the signal.
This subclass is indented under subclass 152. Subject matter in which the receiver is implemented using
at least one surface acoustic wave or charge-transfer (e.g., CCD) structure.
This subclass is indented under the class definition. Subject matter including apparatus wherein a pulse signal
is received and retransmitted usually at a higher energy level.
Multiplex Communications,
subclasses 279 and 293 for wireless and wired duplex repeaters
respectively, subclass 315 for a wireless multiplex repeater, subclass
492 for a frequency division multiplexing repeater, and subclass
501 for a time division multiplexing repeater.
This subclass is indented under subclass 211. Subject matter including conversion (e.g., multilevel
to binary or parallel-serial-parallel) or where
signal pulses are regenerated as regards shape and instant of occurrence.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 165+ for miscellaneous rectangular or clock waveform
regeneration and subclass 317 for distortion by limiting or clipping.
This subclass is indented under subclass 214. Subject matter having a closed-loop electronic servomechanism
the output of which locks onto and tracks a received clock signal
to provide the frequency and phase aligned receiver clock.
This subclass is indented under the class definition. Subject matter wherein the transmission system, transmitter, or
receiver may be altered to alternately send either digital or analog information.
(1)
Note. Systems or elements that simultaneously convey
analog and digital information are not in this class but in Class 370, Multiplex. Systems
wherein the digital data is the address signal for the analog message
are not here but in Class 340, subclasses 7.2-7.63.
This subclass is indented under subclass 216. Subject matter including a means to automatically quiet
the receiver by reducing its gain in response to a specified characteristic
of the input digital signal.
This subclass is indented under the class definition. Subject matter where the ground or water supplies the natural
medium for the transmission of pulse or digital signals.
(1)
Note. The subject matter of this subclass has a
specific underground or underwater structure at each station.
This subclass is indented under the class definition. Subject matter in which a transmitter and a receiver are
at the same location and transmit and receive over the same medium
to-and-from the same remote station.
(1)
Note. The simultaneous operation of a transmitter
and receiver is a duplex operation and is classified in Class 370, Multiplex
Communications, subclasses 276+.
(2)
Note. This and indented subclasses accept nominal
recitation of a digital data processing system or function in combination
with transceivers and data sets. Significant digital data
pre- and postprocessing in combination with transceivers
are classified elsewhere.
Electrical Computers and Digital Data Processing
Systems: Input/Output,
subclasses 1+ for transferring data from one or more peripherals
to one or more computers or digital data processing systems for
the latter to process, store, or further transfer
or for transferring data from the computers or digital data processing
systems to the peripheral of information processing system.
This subclass is indented under subclass 219. Subject matter wherein the transceiver or transceiver"s
component is compared by connecting a received path to a transmitted
path and monitoring the output as an indication of the condition
of the transceiver or transceiver"s component.
This subclass is indented under subclass 219. Subject matter including a device that transform a characteristic
of a typical two level pulse or digital data signal into another
form suitable for transmission over a transmission circuit.
(1)
Note. An example of a modem is a device which converts
two level pulse signals into two tone signals.
Electrical Computers and Digital Data Processing
Systems: Multicomputer Data Transferring, appropriate sublassesfor data transferring among multiple computer
or digital data processing system.
Electrical Computers and Digital Data Processing
Systems: Input/Output,
subclasses 1+ for transferring data from one or more peripherals
to one or more computers or digital data processing systems for
the latter to process, store, or further transfer
or for transferring data from the computers or digital data processing
systems to the peripheral of information processing system.
This subclass is indented under subclass 222. Subject matter in which the transmitted characteristic or
pulses to be transmitted vary the phase or frequency of a carrier
wave.
Telecommunications,
subclasses 67.11 through 67.7for modulated carrier system testing;
subclasses 115.1-115.4 for transmitter
testing; and subclasses 226.1-226.4
for receiver testing.
This subclass is indented under subclass 224. Subject matter including a means for measuring the speed
at which digital information is transmitted or received.
This subclass is indented under subclass 224. Subject matter including a means for measuring abrupt, spurious
variations in the phase of the frequency modulation of successive
pulses referenced to the phase of a continuous oscillator.
This subclass is indented under subclass 224. Subject matter including a means for displaying to a human
observer digital information concerning the system characteristics
being measured.
This subclass is indented under the class definition. Subject matter including a delay line tapped at the pulse
or discrete step interval; a set of adjustable attenuators
connected to each tap, except for a main tap, which
attenuators can be used to multiply remaining tap signals by any
number between 1 and minus 1; and a summing network.
(1)
Note. Equalizers, per se, if they
include a means to perform mathematical calculations, are
found in Class 708, subclasses 300+ and 819.
(2)
Note. Equalizers, per se, are
classified in Class 333. See "SEARCH CLASS" below.
To be classified here, there must be a pulse or digital
communication apparatus.
Wave Transmission Lines and Networks,
subclass 18 for automatically controlled systems with control
of equalizers or delay network; and subclass 28 for coupling
networks with equalizer.
This subclass is indented under subclass 229. Subject matter having means responsive to the received pulses
for adjustment of the attenuators (i.e., nonmanual).
This subclass is indented under subclass 230. Subject matter in which there is an initial adjustment of
the automatic equalizer prior to use or where a test pulse is sent
through the communication channel to determine what the equalizer
settings should be.
This subclass is indented under subclass 230. Subject matter where the equalizer tap adjustment is automatically
changed for optimum equalization using the normal message data signals.
(1)
Note. The term "normal message data signals" excludes
special calibration signals.
This subclass is indented under subclass 232. Subject matter wherein the equalized signal is the sum of
the outputs of the forward and feedback part of the equalizer.
(1)
Note. The forward part is a linear transversal equalizer.
Decisions made on the equalized signal are fed back via a second
transversal filter (i.e., feeback
part).
(2)
Note. The DFE generally eliminates the intersymbol
interference(ISI).
This subclass is indented under subclass 232. Subject matter wherein the delay line taps of the equalizer
are spaced at an interval T which is less than, or a fraction
of the symbol interval.
(1)
Note. The cascaded equalizers combined with a fractionally
spaced equalizer claimed is classified herein.
This subclass is indented under subclass 232. Subject matter in which the received signal is processed
to provide two components, one which differs in phase from
the other by 90 degrees.
This subclass is indented under subclass 232. Subject matter including either a device which stores a
number and which, on receipt of another number, adds
the two and stores the sum, or a counter with the capability
of counting in an ascending or descending order.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 1+ for miscellaneous pulse characteristic discriminating
and subclasses 100+ for miscellaneous pulse charateristic
modifying.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 31+ for miscellaneous circuits providing pulse width
or spacing discriminating and subclasses 172+ for miscellaneous
rectangular or pulse waveform width control.
Multiplex Communications,
subclass 205 for a multiplexing system using both pulse width
and pulse position modulations, and subclass 212 for a multiplexing
system using pulse width modulation.
This subclass is indented under the class definition. Subject matter in which the information to be transmitted
is conveyed by means of the relative position of the pulses in a
series of transmitted pulses, the time or spacing between pulses, or
the repetition rate (frequency) of the pulses.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 1+ for miscellaneous pulse characteristic discriminating
and subclasses 100+ for miscellaneous pulse characteristic
modifying.
Multiplex Communications,
subclass 205 for a multiplexing system using both pulse width
and pulse position modulations, and subclass 213 for a multiplexing
system using pulse position modulation.
This subclass is indented under the class definition. Subject matter where the width of the frequency spectrum
of a pulse or digital signal is either reduced or expanded.
Data Processing: Speech Signal Processing, Linguistics, Language
Translation, and Audio Compression/Decompression,
subclasses 500+ for bandwidth reduction or expansion of audio signals.
This subclass is indented under subclass 240. Subject matter wherein the signal source is a sequence
of images which normally vary with time and are intended to portray
motion.
(1)
Note. The signal source is originally in or converted
to digital format before the frequency range compression process.
This subclass is indented under subclass 240.03. Subject matter wherein the number of discrete signal amplitudes
is varied according to signal characteristics determined upstream from
the quantization process.
This subclass is indented under subclass 240.03. Subject matter wherein the number of discrete signal amplitudes
is varied according to signal characteristics determined downstream
from the quantization process.
This subclass is indented under subclass 240.02. Subject matter wherein the coding process is varied according
to signal characteristics determined upstream from the coding process.
This subclass is indented under subclass 240.02. Subject matter wherein the coding process is varied according
to signal characteristics determined downstream from the coding process.
This subclass is indented under subclass 240.01. Subject matter wherein coding is performed on the basis
of shapes, objects, or other features contained
within images.
This subclass is indented under subclass 240.08. Subject matter wherein objects in images are coded by approximating
the shape of each object by polygons.
This subclass is indented under subclass 240.01. Subject matter wherein the value of an image portion is
predicted based on the value of an earlier or later image portion.
This subclass is indented under subclass 240.1. Subject matter wherein the value of an image portion is
predicted based on the values of both earlier and later (transmitted/received) image portions.
This subclass is indented under subclass 240.16. Subject matter wherein the spatial change has increments
equal to half the distance between two picture elements.
This subclass is indented under subclass 240.18. Subject matter wherein the mathematical transformation involves
the use of an oscillation waveform which persists only one or a few
cycles.
This subclass is indented under subclass 240.01. Subject matter wherein a limited number of image values
are stored in a codebook and used to represent the input image values.
This subclass is indented under subclass 240.01. Subject matter wherein image data are selectively assigned
codes such that the most frequently occurring values receive the
shortest codes.
This subclass is indented under subclass 240.01. Subject matter involving details of a decoding process which
is not merely the converse of the coding process.
This subclass is indented under subclass 240.26. Subject matter wherein the additional signal processing
involves the detection or correction of errors in the coding process.
This subclass is indented under subclass 240.26. Subject matter wherein the additional signal processing
involves maintaining a proper time or phase correspondence between the
coded signals.
This subclass is indented under subclass 240.26. Subject matter wherein the additional signal processing
involves blocking or separating data or signals before or after
the coding process.
This subclass is indented under subclass 240. Subject matter wherein the pulse or digital signal to be
transmitted is sampled or compared and then converted into a digital
pulse train which represents the amplitude of the sampled signal
at the instant of sampling or comparison, and this digital
pulse train is transmitted so it may be reconverted into a duplicate
of the original signal at a receiver.
This subclass is indented under the class definition. Subject matter in which a signal to be transmitted is sampled
or compared and then converted into a digital pulse train which
represents the amplitude of the sampled signal at the instant of
sampling or comparison, and this digital pulse train is
transmitted so it may be reconverted into a duplicate of the original
signal at a receiver.
This subclass is indented under subclass 242. Subject matter in which there is a correction made for errors
or inaccuracies in the encoding of the analog signal.
This subclass is indented under subclass 242. Subject matter where the difference between the actual amplitude
and a predicted, or locally decoded, value of
the amplitude is encoded and transmitted.
This subclass is indented under subclass 244. Subject matter including a means for converting the instantaneous
amplitude of the transmitted signal to the nearest of a fixed number of
discrete amplitude levels, or reverse quantizer.
This subclass is indented under subclass 247. Subject matter where whether a pulse is sent or not is determined
by a criteria other than the amplitude difference of the sampled
and locally decoded waveforms.
This subclass is indented under subclass 247. Subject matter in which the size of the incremental amount
is variable over a wide dynamic range in response to predetermined
patterns in the transmitted series of digital bits or "delta bits" (delta
modulation pulse train).
This subclass is indented under subclass 249. Subject matter where the delta modulation pulse train is
replaced, for transmission purposes, by a derived
pulse train containing fewer pulses, and converting the
derived pulse train back to the delta modulation pulse train at the
receiver.
This subclass is indented under subclass 249. Subject matter in which the companding is instantaneous.
(1)
Note. There are two types of syllabic adaptative
modulators namely, the analog syllabic adaptative modulators
and the digital syllabic adaptative modulators depending on whether
the gain control signal of the amplifier is derived from the input
analog input signal or from the coded digital output signal. The
gain control signal may be derived from the input analog signal
using a simple envelope detector. Similarly, the gain
control signal may be derived from the digital output by means of
a syllabic filter. Such syllabic adaptative modulators
will provide a continuous adaptation of the gain of the amplifier
so as to vary the amplitude of the steps of the integrator accordingly. The
instantaneous adaptation or companding is derived from the digital
output signal on a short time basis.
This subclass is indented under subclass 242. Subject matter where there is provision for removing or
correcting for the effects of extraneous pulses or distortion.
This subclass is indented under the class definition. Subject matter where pulses are radiated into free space
but are not modulated onto a carrier wave.
This subclass is indented under subclass 257. Subject matter including an inductive coupling which is
used between the driver and the transmission line or between the
receiver and the transmission line for isolating the d.c. value.
This subclass is indented under the class definition. Subject matter using alternating, sine, or similar
wave currents or using pulsating currents in the transmission and
reception of pulse or digital communications.
(1)
Note. A system includes both a transmitter and a
receiver.
Miscellaneous Active Electrical Devices, Circuits, and
Systems,
subclasses 1+ for miscellaneous pulse characteristic discriminating
and subclasses 100+ for miscellaneous pulse characteristic
modifying.
This subclass is indented under subclass 259. Subject matter in which more than one transmission channel
is utilized to convey one pulse train.
(1)
Note. A channel is a normally independent transmission
path.
(2)
Note. Multi-carrier modulation techniques (also
known as orthogonal frequency division multiplexing or discrete multi-tone
modulation) are properly classified here, rather
than in Class 370, unless they are used to transmit multiple sources
of information data.
Multiplex Communications, appropriate subclasses for frequency division multiplexing
where multiple sources of information data are transmitted over
a common transmission medium.
This subclass is indented under subclass 260. Subject matter in which the transmitted signal can be represented
as the superposition of two modulated signals, each being
obtained by pulse amplitude modulation of a signal sequence on a
sinusoidal carrier, the two signal sequences being generated
in synchronization at the same rate, and the two carriers
being of the same frequency but 90 degrees apart in phase.
This subclass is indented under subclass 261. Subject matter for choosing an estimate code word for each
possible received sequence of a demodulation output.
(1)
Note. This method is generally used for decoding
the convolution codes.
Error Detection/Correction and Fault Detection/Recovery,
subclasses 786+ for digital data error correction having a convolution
code, particularly subclasses 794 and 795 for maximum likelihood
and Viterbi decoding.
This subclass is indented under subclass 261. Subject matter where the binary data rate is above the Nyquist
rate (equal to twice the transmission bandwidth, and
commonly regarded as the upper limit on the rate of binary data
transmission) thereby dispersing the individual input pulses
over more than one signalling interval.
This subclass is indented under subclass 261. Subject matter for improving the noise immunity of digital
transmission system without bandwidth expansion or reduction of
data rate.
(1)
Note. The encoder employs redundant nonbinary modulation
in combination with a finite-state encoder which governs
the selection of modulation signals to generate the coded signal
sequence.
This subclass is indented under subclass 260. Subject matter where the two or more channels carrying the
same message go from the transmitter to the receiver via different
paths, frequencies, or times of transmission.
This subclass is indented under subclass 259. Subject matter in which the pulses are multiplied with a
carrier wave so as to produce and transmit at least one sideband
equal to the carrier plus or minus the baseband.
(1)
Note. In amplitude modulation the amplitude of the
carrier wave does not change. The carrier wave can represent the
average amplitude of the envelope and, since this is the
same irrespective of the presence or absence of modulation, the
carrier wave transmits no information. The information
is carried by the sidebands.
This subclass is indented under subclass 268. Subject matter wherein the phase or frequency of the amplitude
modulated carrier wave is shifted between at least two phases or
frequencies.
Modulators,
subclasses 120+ for a frequency modulator incorporating amplitude
modulation and subclass 145 for a phase modulator incorporating
amplitude modulation.
This subclass is indented under subclass 268. Subject matter where less than two complete sidebands are
transmitted, with or without the carrier or two complete
sidebands are transmitted without the carrier.
Telecommunications,
subclasses 46 and 47 for suppressed carrier and single or vestigial
sideband systems; subclass 109 for amplitude modulation transmitters; and
subclasses 202 through 204 for amplitude modulated receivers.
This subclass is indented under subclass 259. Subject matter where the digital information or pulses to
be transmitted vary the phase angle or frequency of a carrier wave.
(1)
Note. In angle modulation, the total energy
content of the output spectrum is generally kept constant.
The amplitude of the carrier component depends on the modulation
index.
Demodulators,
subclasses 315+ for frequency demodulators, subclasses 300+ for
a frequency shift keying demodulator, per se, and
subclasses 304+ for a phase shift keying demodulator, per
se.
This subclass is indented under subclass 271. Subject matter where the instantaneous frequency of the
pulse or digitally modulated carrier wave is shifted (generally
between two frequencies) according to the presence or absence
of a pulse, or a mark or space, being transmitted.
This subclass is indented under subclass 272. Subject matter wherein the difference between the mark and
space frequencies is at the minimum value still presenting orthogonality (zero cross-correlation) between
the mark and space signals and thus providing for efficient detection
of the data.
(1)
Note. Continuous phase is maintained at the mark-space
transitions.
This subclass is indented under subclass 272. Subject matter in which the carrier frequency is shifted
after one or less cycle of the carrier has been transmitted.
This subclass is indented under subclass 272. Subject matter wherein one complete sideband, with
or without the carrier wave and with or without the complimentary
sideband, is utilized.
This subclass is indented under subclass 272. Subject matter with provision for correction or reduction
of distortion or for removing or correcting for the effects of extraneous
pulses.
This subclass is indented under subclass 271. Subject matter wherein the instantaneous phase of the carrier
wave departs from a reference phase in accordance with the transmission
of pulses.
This subclass is indented under subclass 279. Subject matter where the carrier is an elementary alternating
current signal having for each data bit a zero crossing in the same
direction at the beginning of each bit and also at the end of each
bit, a constant duration, a zero crossing only
once intermediate the beginning and the end of each bit, the
intermediate zero crossing representing one of the two signalling
conditions when occurring before the middle of the data bit and
the other of the two signalling conditions when occurring after
the middle of the data bit.
This subclass is indented under subclass 279. Subject matter where there is provision for correction or
reduction of the effects of extraneous pulses or of distortion of
the wave shape of the transmitted signals.
This subclass is indented under subclass 259. Subject matter with provision for correction or reduction
of distortion of the wave shape of the carrier wave or for the correction
or reduction of the effects of extraneous pulses.
Electrical Computers: Arithmetic Processing
and Calculating,
subclasses 300+ and 819 for filters and equalizers which perform
mathematical functions during operation.
This subclass is indented under the class definition. Subject matter in which the transmitted pulse waveform has
more than two discrete amplitude levels.
This subclass is indented under subclass 286. Subject matter wherein the received or transmitted signal
is compared with a reference voltage to determine the discrete amplitude level.
This subclass is indented under subclass 286. Subject matter including one or more insulated conductors
arranged to transmit the pulse waveform from one locality to another.
This subclass is indented under subclass 286. Subject matter where the binary data rate is above the Nyquist
rate (equal to twice the transmission bandwidth, and
commonly regarded as the upper limit on the rate of binary data
transmission) thereby dispersing the individual input pulses
over more than one signalling interval.
This subclass is indented under subclass 286. Subject matter where the average transmitted amplitude level
for a predetermined group of bits is reduced as far as possible
in attempting to reduce d.c. components.
This subclass is indented under subclass 286. Subject matter in which the transmitter (coder) and
receiver (decoder) operate in predetermined timed
relationship.
This subclass is indented under subclass 293. Subject matter having a closed-loop electronic servomechanism
the output of which locks onto and tracks a received clock signal
to provide the frequency and phase aligned receiver clock.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 291+ for miscellaneous circuits producing a clock or
a pulse wave form.
This subclass is indented under subclass 295. Systems where any undesired modulation components accompanying
a desired modulated carrier wave signal, which components
are due to electrical disturbances within the useful frequency band
or any undesired carrier wave distortion and which may originate
at a source external to the transmitter or which may be generated
internally in the transmitter, are reduced, eliminated
or compensated for, or where the transmitted signal may, prior
to transmission, be distorted in a manner complementary
to the distortion introduced in the transmission medium.
This subclass is indented under subclass 295. Subject matter in which the transmitted signal can be represented
as the superposition of two modulated signals, each being
obtained by pulse amplitude modulation of a signal sequence on a
sinusoidal carrier, the two signal sequences being generated
in synchronization at the same rate, and the two carriers
being of the same frequency but 90 degrees apart in phase.
This subclass is indented under subclass 295. Subject matter including two or more transmitters transmit
the same messages through two or more channels via different paths, frequencies or
times of transmission.
This subclass is indented under subclass 295. Subject matter in which the pulses are multiplied with a
carrier wave so as to produce and transmit at least one sideband
equal to the carrier plus or minus the baseband.
(1)
Note. In amplitude modulation the amplitude of the
carrier wave does not change. The carrier wave can represent the
average amplitude of the envelope and, since this is the
same irrespective of the presence or absence of modulation, the
carrier wave transmits no information. The information
is carried by the sidebands.
This subclass is indented under subclass 300. Subject matter where less than two complete sidebands are
transmitted, with or without the carrier, or two
complete sidebands are transmitted without the carrier.
This subclass is indented under subclass 295. Subject matter where the digital information or pulses to
be transmitted vary the phase angle or frequency of a carrier wave.
(1)
Note. In angle modulation, the total energy
content of the output spectrum is generally kept constant.
The amplitude of the carrier component depends on the modulation
index.
Demodulators,
subclasses 315+ for frequency demodulators, subclasses 300+ for
a frequency shift keying demodulator, per se, and
subclasses 304+ for a phase shift keying demodulator, per
se.
This subclass is indented under subclass 302. Subject matter where the frequency of the carrier wave shifts
between predetermined values in accordance with the value of the
modulating pulse wave.
This subclass is indented under subclass 303. Subject matter where the transmitter is connected to an
antenna circuit which is tuned to the instantaneous frequency of
the transmitted carrier wave.
This subclass is indented under subclass 303. Subject matter wherein the differences between the mark
and space frequencies is at the minimum value still preserving orthogonality (zero cross-correlations) between
the mark and space signals and thus providing for efficient detection
of the data. Continuous phase is maintained at the mark-space
transitions.
This subclass is indented under subclass 303. Subject matter where the modulated carrier wave is generated
by altering the frequency of an oscillator in the transmitter.
This subclass is indented under subclass 303. Subject matter where the carrier wave is generated by switching
between two or more oscillators of differing frequency
This subclass is indented under subclass 302. Subject matter where the carrier wave is modulated by varying
its phase in accordance with the pulses to be transmitted.
This subclass is indented under subclass 295. Subject matter wherein the output signal of the transmitter
is initiated and terminated by a keying device, such as
a manually or automatically operated switch.
(1)
Note. The keying device may control the active elements
of the transmitter (oscillator or modulator) or
the coupling circuits.
(2)
Note. Where the claims are drawn to a keying device
controlling an oscillator or an amplifier without additional details
of the transmitter, classification is in Class 331, subclasses
172+ or Class 330, respectively.
This subclass is indented under subclass 309. Subject matter wherein the keying device has its control
part located at a point some distance removed from the transmitter.
(1)
Note. This subclass includes relay controlled keying, wherein
the operator key controls the relay, the armature controlled
contacts being in the transmitter circuit.
(2)
Note. This distance between the operator key and
the transmitter circuit controlled thereby may be considerable or the
distance may be small as with relay controlled keying.
This subclass is indented under subclass 309. Subject matter wherein the keying of the transmitter is
automatically controlled as opposed, for example, to
a manual control.
(1)
Note. The automatic keying devices of this subclass
include rotating cylinders, disks, etc., with
cams or conductive segments arranged in a predetermined fashion
for closing contacts in the transmitter circuit and controlling
the transmission of intelligence.
This subclass is indented under subclass 309. Subject matter wherein the keying device for controlling
the operation of the transmitter is in the power or bias voltage
supply circuit.
This subclass is indented under subclass 309. Subject matter including provision to eliminate or prevent
the electrical disturbances produced by abrupt operation of the
key.
This subclass is indented under subclass 309. Subject matter including an auxiliary electron discharge
tube in the keying circuit, the conduction of which controls
the operation of the transmitter and is responsive to the keying means.
This subclass is indented under subclass 309. Subject matter including means controlled by the keying
operation to absorb the oscillations during spacing periods as when
the transmission of intelligence is by marks and spaces, or to
change the impedance or dimension of the antenna to cause modulation
of the carrier.
This subclass is indented under the class definition. Subject matter including apparatus to decode, demodulate, or
otherwise recover the transmitted intelligence.
Demodulators,
subclasses 311+ for pulse demodulators, subclasses 300+ for
a frequency shift keying demodulator, per se, and
subclasses 304+ for a phase shift keying demodulator, per se.
Communications: Directive Radio Wave
Systems and Devices (e.g., Radar, Radio
Navigation), appropriate subclasses for radar receivers in which
ranging or position determining is claimed.
This subclass is indented under subclass 316. Subject matter where the received signal is compared to
a reference voltage or current level, the reference level
being automatically adjusted.
This subclass is indented under subclass 317. Subject matter including a circuit that amplifies the difference
between the received signal and the reference signal.
This subclass is indented under subclass 317. Subject matter including a means for eliminating unwanted
DC offset voltages in a receiver for decoding the digitally modulated
signals.
This subclass is indented under subclass 316. Subject matter wherein the receiver extracts a modulating
signal from an input AM signal whose amplitude of a carrier varies
over a continuum of values in accordance with the modulating signal.
This subclass is indented under subclass 320. Subject matter in which the receiver is responsive to pulses
which are amplitude modulated onto a carrier wave in such a manner
that less than a full carrier or less than two complete sidebands
are created by the modulation process.
This subclass is indented under subclass 316. Subject matter where the angle of the sine wave carrier
is varied in accordance with the pulse or digital information.
This subclass is indented under subclass 322. Subject matter including a specified type of circuit for
recovering the pulse or digital signal from the modulated carrier
wave.
Demodulators,
subclasses 311+ for pulse demodulators, subclasses 315+ for
frequency demodulators, subclasses 345+ for phase
demodulators, and subclasses 347+ for amplitude demodulators.
This subclass is indented under subclass 324. Subject matter including a detecting circuit for deriving
additional information from the phase of the carrier signal.
This subclass is indented under subclass 324. Subject matter wherein the demodulator includes a local
oscillator synchronized in phase and frequency with the received
signal.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 156+ for miscellaneous synchronizing circuits having
a phase lock loop.
This subclass is indented under subclass 324. Subject matter including circuits such as logic gates and
counters for processing the angle modulated wave in the receiver.
This subclass is indented under subclass 322. Subject matter in which the phase of the carrier detected
has been varied according to the pulse or digital information.
This subclass is indented under subclass 329. Subject matter in which the bit interval representing one
of the two binary levels is formed by a change in the phase of the
received signal relative to the preceding bit interval, and
the bit interval representing the other of the two binary levels
is formed by the absence of a change of phase of the received signal.
This subclass is indented under subclass 329. Subject matter where the received signal can assume one
of at least three possible phases during a bit interval.
This subclass is indented under subclass 329. Subject matter wherein the data to be detected has been
encoded as a 0-1 transition for one bit of information
and a 1-0 transition for the other bit.
This subclass is indented under subclass 322. Subject matter where the carrier has been modulated by shifting
its frequency in accordance with the pulses transmitted.
This subclass is indented under subclass 334. Subject matter in which the input signal detected has three
or more frequencies representing three or more pieces of information.
This subclass is indented under subclass 334. Subject matter for receiving a signal having frequency shifts
equal to the minimum necessary to distinguish a mark from a space.
This subclass is indented under subclass 334. Subject matter in which one frequency is received over one
channel and the other frequency is received over another separate
channel within the receiver.
(1)
Note. Systems with entirely independent paths between
the transmitter and receiver will not be found here but in subclass
260.
This subclass is indented under subclass 316. Subject matter in which the pulse or digital information
is received on a carrier wave which is turned on and off at a rate
much higher than the signal rate.
This subclass is indented under subclass 338. Subject matter comprising means whereby the local generator
or oscillator is triggered, gated, or otherwise
controlled by the received signal.
(1)
Note. This controlled generator signal is then recorded
or otherwise used.
This subclass is indented under subclass 340. Subject matter wherein a decoding method is used for choosing
an estimate code word for each possible received sequence of a demodulation
output.
(1)
Note. This method is generally used for decoding
the convolution codes.
Error Detection/Correction and Fault Detection/Recovery,
subclasses 786+ for digital data error correction having a convolution
code, particularly subclasses 794 and 795 for maximum likelihood
and Viterbi decoding.
This subclass is indented under subclass 340. Subject matter in which the demodulator locates a predetermined
portion of the pulse such as a maxima, minima, or
zero crossing.
This subclass is indented under subclass 340. Subject matter where a signal to be demodulated is compared
point to point with an internally generated reference signal which
is constructed in such a way that it is at all times a prediction
of what the signal to be demodulated should be at that time.
Electrical Computers: Arithmetic Processing
and Calculating,
subclasses 300+ for digital filters, per se, subclasses
422+ for digital correlators, subclasses 813+ for
analog correlation, and subclass 819 for analog filtering.
This subclass is indented under subclass 316. Subject matter where a receiver frequency response characteristic
is set or adjusted in response to frequency changes in the input
signal or charges in the receiver parameters.
This subclass is indented under subclass 316. Subject matter where the amplification of the receiver is
automatically adjusted in accordance with the strength of the received
signal.
This subclass is indented under subclass 316. Subject matter where the deleterious effects of extraneous
signals are eliminated or suppressed at the receiver.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems, appropriate subclasses and particularly
subclasses 310+ , 384+, and 551+ for
miscellaneous or unwanted signal suppression.
This subclass is indented under subclass 346. Subject matter including two separate receivers receiving
the same signal on two different frequencies or at two different
locations on the same frequency or one receiver receiving the same
signal at different times and combining the two thus received signals
into a more noise free signal.
This subclass is indented under subclass 346. Subject matter wherein the noise is reduced by a frequency
domain or digital sequence filter. The filter may remove
interference or pass only desired signals.
This subclass is indented under subclass 346. Subject matter where noise pulses are eliminated by the
operation of switches to open or short the signal path to delete
the undesired signals.
This subclass is indented under subclass 316. Subject matter including an electromagnetically operated
switch or an electromagnet with an armature which reciprocates within
and along the axis of an energized coil.
This subclass is indented under the class definition. Subject matter in which the amplitude of the transmitted
pulses represents the transmitted information.
Miscellaneous Active Electrical Nonlinear Devices, Circuits, and
Systems,
subclasses 50+ for miscellaneous pulse amplitude discriminating
and subclasses 178+ for miscellaneous rectangular or pulse
waveform amplitude control.
This subclass is indented under the class definition. Subject matter for synchronizing the operation of the receiving
and transmitting mechanisms.
(1)
Note. This subclass may include multiplex techniques
used to control synchronization of the transmitter and receiver; however, when
the information content is multiplexed, classification
is in Class 370.
Data Processing: Speech Signal Processing, Linguistics, Language
Translation, And Audio Compression/Decompression,
subclass 270.1 for speech assisted network.
This subclass is indented under subclass 354. Subject matter wherein the sampling time of a sampler is
synchronized to the transmission baud rate, or twice, or
more of the transmission baud rate.
Data Processing: Speech Signal Processing, Linguistics, Language
Translation, And Audio Compression/Decompression,
subclass 270.1 for speech assisted network.
This subclass is indented under subclass 354. Subject matter in which there is a signal sent from the
receiver to the transmitter to control the synchronization of the
system.
This subclass is indented under subclass 354. Subject matter that receives the synchronizing information
from the information signal itself rather than requiring the transmission
and ultimate reception and separation of a special synchronizing
signal interleaved with the incoming information signal.
This subclass is indented under subclass 359. Subject matter including a circuit for detecting the changes
of a signal level of the received encoded signal.
This subclass is indented under subclass 359. Subject matter wherein the information signal is encoded
as a 0-1 transition for one bit of information and a 1-0
transition for the other bit.
This subclass is indented under subclass 354. Subject matter which uses the transmission and ultimate
reception and separation of a special synchronizing signal interleaved
with the incoming information signal.
This subclass is indented under subclass 362. Subject matter where there are gaps created in the transmitted
bit stream in which synchronization bits are transmitted.
This subclass is indented under subclass 362. Subject matter where the synchronization signals are distinguishable
from data signals by a differing amplitude, polarity, length, or
frequency.
This subclass is indented under subclass 362. Subject matter in which the synchronization signal is a
multidigit word which is not a member of the set of valid data words.
This subclass is indented under subclass 365. Subject matter where the unique synchronizing word has the
property of being produced by a definite calculation process while
simultaneously satisfying one or more of the standard tests for
statistical randomness.
This subclass is indented under subclass 369. Subject matter having a variable time interval between successive
bits, characters or events of the incoming data stream.
This subclass is indented under subclass 371. Subject matter wherein a first in-first out (FIFO) storage
is operated to receive data that is synchronized with a write clock
from the input signal and therefrom synchronized with the read clock
of the FIFO storage.
This subclass is indented under subclass 371. Subject matter wherein the receiver clock and received data
are brought into frequency and phase alignment or coherence.
This subclass is indented under subclass 373. Subject matter including a means for controlling the voltage
which applied to the voltage control oscillator (VCO) as
to change the frequency of the phase lock loop.
This subclass is indented under subclass 373. Subject matter including a frequency detecting device to
ensure the frequency alignment before a phase detector adjusts the
phase locking.
This subclass is indented under subclass 373. Subject matter having a closed-loop electronic servomechanism
the output of which locks onto and tracks a received signal to provide
the frequency and phase aligned receiver clock.
This subclass is indented under the class definition. Subject matter not provided for in any of the preceding
subclasses of this class.
E-SUBCLASSES
The E-subclasses in U.S. Class 375 provide for Spread Spectrum
techniques in signal modulation for transmission and systems for
the transmission of digital video signal using pulse code modulation.
This maingroup provides for subject matter utilizing a data
modulated signal which has its energy spread over a transmitted
bandwidth which is much greater than the bandwidth or rate of information
being sent. This subclass is substantially the same in scope as
ECLA classification H04B1/69.
SYSTEMS FOR THE TRANSMISSION OF TELEVISION SIGNALS USING
PULSE CODE MODULATION (EPO):
This main group provides for systems for the transmission
of television signals using pulse code modulation, i.e. transmission
systems wherein the television signal is a digital video signal
or a bit stream carrying visual content; e.g., systems, devices
and methods for video bit stream assembling, disassembling, transport,
processing, delivery or control, for source coding or decoding of
digital video signal, for error protection, detection or correction
of digital video signal, for channel coding or decoding of digital
video signal. This subclass is substantially the same in scope
as ECLA classification H04N7/24.
This subclass is indented under subclass E7.001. This subclass
is substantially the same in scope as ECLA classification H04N7/52.
(1)
Note: Subject matter of this subclass includes assembling
of a system multiplex stream from mono-media streams or disassembling
of a system multiplex stream into mono-media streams.
Any Foreign patents or non-patent literature from subclasses
that have been classified have been transferred directly to FOR
Collections listed below. These collections contain only foreign
patents or non-patent literature. The parenthetical references
in the collection titles refer to the abolished subclasses from
which these collections were derived.
Subject matter utilizing a data modulated signal
which has its energy spread over a trans bandwidth which is much
greater than the bandwidth or rate of information being sent.
Subject matter wherein the spread spectrum signals
are made up of at least two different spread spectrum techniques
such as (a) simultaneous frequency hopping and direct sequence modulations,
(b) simultaneous time and fre hopping, or (c) simultaneous time-hop
and direct sequence modulations.
Subject matter including a system in which the wideband
signal is generated by jumping from one frequency to another over
a large number of frequency choices
Subject matter including a system wherein waveforms
are transmitted at times which are selected from among a plurality
of time slots, with the selection of time slot being pseudo-random
if desired.
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