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, Data Structures, or Document Processing; 708,
Electrical Computers: Arithmetic Processing and Calculating; 709,
Electrical Computers and Digital Processing Systems: Multiple Computer
or Process Coordinating; 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,
subclass 146.2 for Digital comparator systems, subclasses 350+ for
Directive systems; subclassses 825+ for the remote control
of a device external to a communication system (e.g., model airplane); subclass
825.52 for addressing of a particular pulse receiver; subclasses
825.57+ for pulse responsive selective signalling systems;
subclasses 870.01+ for telemetering systems; subclasses
870.18+ 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.
Telecommunication, 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: Multiple Computer or Process Coordinating, 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.
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 200 through 226,for 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 130. 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 13. 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 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 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 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 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 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 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 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 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 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 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 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 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: Multiple Computer or Process Coordinating, 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.
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