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CLASS 455,	TELECOMMUNICATIONS
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SECTION I - CLASS DEFINITION

This is the generic class for modulated carrier wave communications not elsewhere classifiable.

Some art areas excluded from this class are: Alternating or pulsating current telegraphy; Antennas; Broadcast or multiplex stereo; Condition responsive indicating systems with a radio coupling link; Directive carrier wave systems; Multiplex carrier wave communications; Paging via modulated carrier wave; Pulse or digital communications which may be modulated onto a carrier wave; Reflected carrier wave systems (e.g., radar); Selective (e.g., remote control); Telemarketing; Television; Facsimile. (See References to Other Classes, below, for class references.)

SECTION II - LINES WITH OTHER CLASSES AND WITHIN THIS CLASS

The combination of the subject matter of this class (455) and other art environment is generally classified with the other art environment where that environment is significant by virtue of the claimed relationship. For example: Directive systems; Geophysical systems; Radar systems; Radio remote control systems; Telegraph systems; Telemetering systems; Television systems; Facsimile systems (See References to Other Classes, below.)

Subcombinations specific to a modulated carrier wave communication system are classified herein unless classified elsewhere. For example: Demodulation and detector, oscillators, per se, Modulators, per se, and tuners, per se, are classified elsewhere. (See References to Other Classes, below.)

ORGANIZATION OF THIS CLASS

Subclasses 1-355 of this class (455) are limited to radio wave communication systems in which the carrier wave is modulated by a continuous (analog) signals. These subclasses exclude:

(A) Remote control of an external device which is classified in Class 340, subclasses 1.1-16.1.

(B) Multiplexing of signals which represent intelligence; see Class 370.

(C) Pulse or digital signals which represent intelligence; see Class 375.

The above subclasses may include pulse signals which are used to control a transmitter or receiver; however, where the information content is represented by a pulse or digital signal, classification is in Class 375. Subclass 899 of this class (455) is miscellaneous analog or pulse modulation carrier wave communication not elsewhere classified, for example, modulated protons, muons, or neutrino particles utilized for communication of information.

SECTION III - REFERENCES TO OTHER CLASSES

SEE OR SEARCH CLASS:

SECTION IV - GLOSSARY

MODULATED CARRIER WAVE

A wave resulting when the necessary characteristics of an intelligence or information signal are impressed on a carrier wave.

RADIOTELEPHONE SYSTEM

A system for establishing a voice communication link between a base and a mobile transceiver via a wireless carrier wave channel that is allocated for use during a communication link, and wherein the mobile transceiver has a specific assigned call address number.

TELECOMMUNICATIONS

All types of communications systems in which electric or electromagnetic signals are used to transmit modulated carrier wave information between points. The transmission media is via radio wave generally of a frequency above human speech, yet at a frequency lower than infrared frequencies. Radiotelephonic communication via wireless link is included in this class.

SUBCLASSES

1	INTERFERENCE SIGNAL TRANSMISSION (E.G., JAMMING):
	This subclass is indented under the class definition.  Subject matter including means to transmit an interference signal to interfere with a selected signal so as to prevent the intelligible reception of the selected signal. (1) Note. The combination of an interference transmitter with a receiver to select the frequency of the incoming signal it is desired to jam or block, and control means to tune the transmitter to said frequency, is classified in this subclass when the receiver serves solely to determine the frequency of the incoming signal and to control the transmitter. If the receiver portion of the combination is complete (reproduces the intelligence received) the combination is a transceiver and is classified in this class (455), subclasses 73+. (2) Note. Antijamming devices or methods are not classified here, but are found in subclasses 296+. SEE OR SEARCH CLASS: 343,  Communications: Radio Wave Antennas,   subclass 18 for jamming or radar transmissions. 380,  Cryptography,   subclasses 252 through 254for concealment of information by masking of an information bearing signal.

2.01	AUDIENCE SURVEY OR PROGRAM DISTRIBUTION USE ACCOUNTING:
	This subclass is indented under the class definition.  Subject matter including means for indicating, metering, or recording the number of receivers using a radio program, the length of time that a radio program is being used, which of several radio programs is being used, or which radio programs have been broadcast. (1) Note. This subclass is provided for generic devices of this type. Use survey and accounting systems which are designed for a specific type of signal such as television are not classified here but in the class appropriate thereto. SEE OR SEARCH THIS CLASS, SUBCLASS: 3.01+, for wireless program distribution systems. 26.1, for systems to prevent unauthorized use of a signal. SEE OR SEARCH CLASS: 380,  Cryptography,   appropriate subclasses for a cryptographic system to prevent unauthorized use of a signal. 725,  Interactive Video Distribution Systems,   subclasses 1 through 8for billing in a video distribution system and subclasses 9-24 for surveying of receiver use, commercial or program airing verification, and awarding coupon, token, or credit, respectively.

3.01	WIRELESS DISTRIBUTION SYSTEM:
	This subclass is indented under the class definition.  Subject matter including an organized arrangement of transmission links for connecting a plurality of discrete subscribers to a source of information signals. (1) Note. This subclass and its indents are intended to collect devices, such as community antennas (inclusive of wireless local loop or WLL) and national or global networks. (2) Note. Distribution systems including WLL which emphasize a specific type of signal such as television or digital are not classified here but rather in the appropriate class thereto. (3) Note. Police, fire, and other radiotelephone systems which may include some elements of a distribution system are classified elsewhere. See the search notes below. SEE OR SEARCH THIS CLASS, SUBCLASS: 3.05, for two-way wireless local loop. 132, for plural receivers. 149, for a plural output receiver. 272, for plural separate wave collectors combined with a receiver. 500 through 528 and 59-72, for plural transmitters or receivers at separated stations (e.g., police, fire, and other radiotelephone systems which may include some elements of a distribution system). SEE OR SEARCH CLASS: 307,  Electrical Transmission or Interconnection Systems,   subclasses 11 through 87for like systems without limitation of radiant energy path or analog carrier wave. 315,  Electric Lamp and Discharge Devices: Systems,   subclasses 39 and 39.3 for like systems with discharge devices. 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 365 through 508for miscellaneous gating systems. 333,  Wave Transmission Lines and Networks,   subclasses 1 through 137for plural channel systems. 340,  Communications: Electrical,   subclasses 1.1 through 16.1for selective systems with distribution characteristics. 343,  Communications: Radio Wave Antennas,   subclasses 850 through 865for an antenna, per se, with coupling network. 375,  Pulse or Digital Communications,   appropriate subclasses for distribution systems designed for a specific type of digital signal. 725,  Interactive Video Distribution Systems,   for appropriate subclasses.

3.02	Receiver for satellite broadcast:
	This subclass is indented under subclass 3.01.  Subject matter including an antenna for receiving satellite transmissions.

3.03	Remote control of distribution:
	This subclass is indented under subclass 3.01.  Subject matter wherein some functions of a modulated carrier wave source or receiver are supervised or controlled from a remote site. (1) Note. Because of a search note in subclass 3.05, only disclosures of more than mere control in the second directions should be cross referenced thereto. SEE OR SEARCH THIS CLASS, SUBCLASS: 8, for repeater system with failure compensation. 26.1, for unauthorized use prevention systems. 31.1 through 38.5, for systems with additional selectively responsive means. 68 through 72, for control of communication system. 88, for transceiver controlling a separate transceiver or receiver. 92, for remote control of a transmitter. 132, for plural receivers of which one controls another. 352 through 355, for remote control of a receiver. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 12.5 and 13.24 for remote control over a radio link. 380,  Cryptography,   appropriate subclasses for a cryptographic system to prevent unauthorized use of a signal.

3.04	With subscriber selection or switching:
	This subclass is indented under subclass 3.03.  Subject matter including means for a subscriber to selectively receive desired information signals. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 1.1 through 16.1for generic selective systems.

3.05	Two-way:
	This subclass is indented under subclass 3.01.  Subject matter including means for establishing communication in both directions. (1) Note. Wherein the second communication is the notation or reporting of the program watched or listened to, classification is in audience survey and use accounting. (2) Note. Wherein any communication in a system is in pulse form, such system is classified elsewhere. See the search notes below. (3) Note. Wherein any communication in a system is in the form of light waves, such system is classified elsewhere. SEE OR SEARCH THIS CLASS, SUBCLASS: 2.01, for audience survey and use accounting. SEE OR SEARCH CLASS: 359,  Optical: Systems and Elements,   subclasses 109 through 195for an information signal transmitted between an optical transmitter and optical receiver by means of variation in a characteristic of light waves. 375,  Pulse or Digital Communications,   for communication in a system in pulse form.

3.06	Combined with diverse art device (e.g., audio/sound or entertainment system):
	This subclass is indented under subclass 3.01.  Subject matter wherein the distribution system is combined with another art device. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclass 4.37 for selective program control of audio system and subclass 4.4 for selective control of audio system by pulse signal. 381,  Electrical Audio Signal Processing Systems and Devices,   subclasses 2 through 18for stereo broadcasting and subclasses 77-85 for one-way audio signal program distribution.

7	CARRIER WAVE REPEATER OR REPLAY SYSTEM (I.E., RETRANSMISSION OF SAME INFORMATION):
	This subclass is indented under the class definition.  Subject matter comprising means whereby a radiant energy signal wave is received and reradiated at the same or different carrier frequency and usually at a higher energy level and/or in a desired direction. (1) Note. Where the transmitted signal has a different characteristic than the received signal or involves the addition or subtraction of information classification is not in this subclass, but in Class 343 (see notes under subclass 6.5 in the class definition of Class 343). However, if the transmitted signal is on a different carrier frequency from the received signal merely to avoid interference classification is in this subclass. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclasses 70+ for repeaters specific to telegraphy. 330,  Amplifiers,   for amplifiers systems in general, particularly subclass 10 for modulator-demodulator type amplifiers for amplifying direct current or slowly varying alternating current signals. 332,  Modulators,   particularly subclasses 183+ for modulation converters for converting one modulated wave to a differently modulated wave (e.g., pulse modulation to frequency modulation or frequency modulation to amplitude modulation); subclass 108 for plural stage modulation systems wherein each stage is of the same or diverse type of modulation, the last stage being of the pulse modulation type; subclasses 119+ or 145, for plural stage modulation systems wherein the last stage is of the phase or frequency modulation type; and subclasses 151+ for plural stage modulation systems wherein the last stage is of the amplitude modulation type. 333,  Wave Transmission Lines and Networks,   subclass 117 for hybrid-type networks. 340,  Communications: Electrical,   subclass 291 for signal box repeaters which repeat, for example, signals received at a central station to a plurality of fire houses. 343,  Communications: Radio Wave Antennas,   subclasses 5+ for systems and apparatus which include a receiver-transmitter station designed for control by a wave transmitted from a first transmission station and designed to transmit a signal which is different from the received signal, i.e., adds additional information, the system including means to receive the signal transmitted by the receiver transmitter station. Where the signal which is transmitted by the receiver-transmitter is of the same character as the received signal, even though a time-delay is interposed between the time of reception and the time of transmission, the patent is classified in this subclass. 370,  Multiplex Communications,   subclasses 274 , 279, 293, 315+, and 492+ for repeaters using multiplex frequency channels.

8	Failure compensation (e.g., spare channel):
	This subclass is indented under subclass 7.  Subject matter including apparatus for compensating for failure in operation of a repeater station.

9	Monitoring:
	This subclass is indented under subclass 7.  Subject matter including means for measuring or testing the operating condition at a repeater station.

10	Fading compensation:
	This subclass is indented under subclass 9.  Subject matter where the measured quantity is the strength of the received signal and variations in said received signal strength are compensated for.

11.1	Portable or mobile repeater:
	This subclass is indented under subclass 7.  Subject matter wherein a receiving or transmitting station is not permanently mounted in one location, but is either carried by a person or associated with a movable object, such as a vehicle (i.e., mobile repeater station).

12.1	Space satellite:
	This subclass is indented under subclass 11.1.  Subject matter wherein the repeater or relay is associated with an artificial satellite orbiting the earth. SEE OR SEARCH CLASS: 342,  Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),   subclasses 352+ which include a satellite. 343,  Communications: Radio Wave Antennas,   digest 2 for satellite mounted antenna. 370,  Multiplex Communications,   subclasses 316+ for a space satellite repeater using communication techniques.

13.1	With plural repeater or relay systems:
	This subclass is indented under subclass 12.1.  Subject matter having more than one modulated carrier wave and having a repeater or a relay for each modulated carrier wave. (1) Note. The subject matter of this subclass is limited to plural single channel repeaters; whenever plural independent messages are simultaneously transmitted, classification is elsewhere. SEE OR SEARCH CLASS: 370,  Multiplex Communications,   for plural independent messages are simultaneously transmitted,

13.2	Synchronizing of satellites or system:
	This subclass is indented under subclass 12.1.  Subject matter wherein stations in a system are regulated such that each transmits a carrier wave of the same frequency and phase as those carriers transmitted by the other stations. SEE OR SEARCH CLASS: 370,  Multiplex Communications,   subclass 324 for time division multiple access synchronization of space satellites. 375,  Pulse or Digital Communications,   subclasses 354+ for digital network synchronization.

13.3	With antennas feed network or multiple antennas switching:
	This subclass is indented under subclass 12.1.  Subject matter wherein the space satellite has more than one antenna or has a regulation means to control the selection of an antenna. SEE OR SEARCH CLASS: 343,  Communications: Radio Wave Antennas,   subclasses 705+ for antennas with aircraft.

13.4	Power control:
	This subclass is indented under subclass 12.1.  Subject matter including means to regulate the output power in the satellite system.

14	With transmission line:
	This subclass is indented under subclass 7.  Subject matter where the repeater or relay is inserted in a waveguide or other type of transmission line.

15	Two separate way transmission:
	This subclass is indented under subclass 7.  Subject matter where the relay or repeater operates in at least two directions. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclasses 71.1+ for automatic two-way repeaters specific to telegraphy. 370,  Multiplex Communications,   subclasses 276+ for duplex communications.

16	Simultaneous using plural repeaters at each location:
	This subclass is indented under subclass 15.  Subject matter where the repeater operates in at least two directions at the same time by means of a plurality of repeaters at the same location.

17	Plural modulated carriers:
	This subclass is indented under subclass 7.  Subject matter wherein there is more than one modulated carrier wave being repeated or relayed at the same time. SEE OR SEARCH CLASS: 370,  Multiplex Communications,   subclasses 204+ for plural diverse modulation techniques.

18	With delay or recording:
	This subclass is indented under subclass 7.  Subject matter including a device to time delay or make a permanent record of the modulated carrier wave. SEE OR SEARCH CLASS: 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 261+ for miscellaneous output waveform production delay. 333,  Wave Transmission Lines and Networks,   subclasses 138 through 164for passive delay networks.

19	Common antenna:
	This subclass is indented under subclass 7.  Subject matter where the modulated carrier wave is received and transmitted on the same antenna.

20	With frequency conversion:
	This subclass is indented under subclass 7.  Subject matter including apparatus to change the frequency of the modulated carrier wave. (1) Note. For classification in this subclass it is not necessary that the carrier frequency of the transmitted signal be different from the carrier frequency of the received signal. For example, the frequency of the received carrier wave may be converted to a lower frequency for purposes of amplification and then be reconverted to the original frequency for transmission. SEE OR SEARCH CLASS: 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 113+ for miscellaneous frequency control or conversion. 331,  Oscillators,   subclasses 37+ for means to produce a beat frequency by combining the output of two or more oscillators. 332,  Modulators,   appropriate subclasses for frequency conversion modulation systems, per se.

21	With demodulator:
	This subclass is indented under subclass 20.  Subject matter including apparatus for removing the intelligence from the received signal. SEE OR SEARCH CLASS: 329,  Demodulators,   for demodulators, per se. 330,  Amplifiers,   subclass 10 for direct current or low frequency alternating current amplifiers of the modulator-demodulator type.

22	Plural conversion stages:
	This subclass is indented under subclass 20.  Subject matter including more than one successive conversion stage. SEE OR SEARCH CLASS: 332,  Modulators,   especially subclasses 108, 119+, 145, and 151+ for plural modulation stage modulators.

23	Frequency or phase modulation:
	This subclass is indented under subclass 7.  Subject matter where the carrier wave is modulated by varying its frequency or phase in accordance with the information signal. SEE OR SEARCH CLASS: 329,  Demodulators,   subclasses 315+ for frequency demodulators and subclasses 345+ for phase demodulators. 332,  Modulators,   subclasses 183+ for modulation converters (e.g., FM. to A.M.); and subclasses 144+ and 117+ for phase or frequency modulators, per se.

24	Transmitter-receiver feedback compensation:
	This subclass is indented under subclass 7.  Subject matter including apparatus to prevent unwanted feedback between the transmitter and the receiver. SEE OR SEARCH THIS CLASS, SUBCLASS: 78, for a transceiver with transmitter-receiver interaction prevention. SEE OR SEARCH CLASS: 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclass 593 for miscellaneous oscillation prevention. 330,  Amplifiers,   subclasses 75+ for amplifiers with feedback means including negative feedback for preventing oscillation. 370,  Multiplex Communications,   subclasses 278 and 282+ for transmit/receive interaction control in duplex communications.

25	Directive antenna:
	This subclass is indented under subclass 7.  Subject matter including an antenna which is more responsive in one direction than in another. SEE OR SEARCH CLASS: 343,  Communications: Radio Wave Antennas,   subclass 18 for structure for reflecting radio waves; subclasses 100+ for means for sending and/or receiving radio wave energy which is characterized by some quality that varies according to the relative direction, position and/or plane or polarization of the sender and receiver; and subclasses 700+ for antennas, per se, including directional antennas and antennas combined with reflecting and/or refracting means.

26.1	USE OR ACCESS BLOCKING (E.G., LOCKING SWITCH):
	This subclass is indented under the class definition.  Subject matter which blocks access to a signal source or otherwise limits usage of modulated carrier equipment. SEE OR SEARCH CLASS: 194,  Check-Actuated Control Mechanisms,   appropriate subclasses for a coin controlled device of general utility. 380,  Cryptography,   appropriate subclasses for signal scrambling and subclasses 252 through 254for encryption by signal masking.

39	TRANSMITTER AND RECEIVER AT SEPARATE STATIONS:
	This subclass is indented under the class definition.  Subject matter including at least one transmitting device which converts analog information signals (e.g., audio) into modulated carrier wave signals, a carrier wave transmission medium, and at least one receiving device whereby the information or modulating signal transmitted will be derived from the received modulated carrier wave signals. (1) Note. A system, in order to be classified in this subclass and its indents must include a means whereby the information transmitted is transmitted by means of a sinusoidal electromagnetic carrier wave. Systems wherein the intelligence to be conveyed is transmitted by dot and dash (i.e., presence or absence of a unidirectional or direct current wave) are found elsewhere. Systems wherein the intelligence conveyed is pulse or digital information are found elsewhere. Systems wherein the intelligence to be conveyed by a varying current without a carrier wave are found elsewhere. Systems which are properly classifiable, as a result of some significantly claimed art limitations, in another class will not be classified here. (2) Note. The subject matter classifiable here will generally comprise both the means for origination and modulating a carrier wave according to the information, desired to be transmitted, and a means for receiving the modulated carrier wave and deriving the desired information. However, where the claimed subject matter includes claims reciting the specific details of a transmitter or receiver or transceiver and broadly include another receiver, transceiver, or transmitter of different type by name only, the patent will be classified here and cross-reference down to the appropriate subclass below which contains the particular transmitter, transceiver, or receiver claimed. (3) Note. The systems in this and the indented subclasses comprises at least one transmitter and receiver device which devices are located at an appreciable distance one from the other. However, patents in which the claimed subject matter includes transmitter-receiver means at a single station (transceiver) are also to be found here providing sufficient structure is recited whereby the transmitter-receiver means cooperates with and influence or is influenced by a further receiver or transmitter at a distance; providing, that the claimed subject matter does not include a structure limiting the system to use of radiant energy as defined in the definition of Class 343 or to use in some other art class device. SEE OR SEARCH THIS CLASS, SUBCLASS: 7+, for transmitter-receiver repeater systems. 73+, for complete stations wherein the transmitter and receiver are at the same point. 91+, for transmitter, per se. 130+, for receivers, per se. 600+, for light wave communications. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclasses 2+ for various telegraph systems which are limited to the transmission and reception of telegraph signals; subclasses 24+ for teleprinting systems; subclasses 45+ for loaded carrier wave transmission lines; and subclass 118 for miscellaneous telegraph receivers. 244,  Aeronautics,   particularly subclasses 175+ for systems for automatically controlling aircraft by means of electrical apparatus which may utilize modulated carrier waves for control. 246,  Railway Switches and Signals,   particularly subclasses 7+ and 28+ for carrier wave systems employed in railway signalling. 307,  Electrical Transmission or Interconnection Systems,   subclass 117 for switching systems controlled by radiant energy; and subclass 129 for frequency responsive switching space discharge device or lamp systems. 315,  Electric Lamp and Discharge Devices: Systems,   subclasses 149+ for radiant energy controlled space discharge device or lamp systems. 318,  Electricity: Motive Power Systems,   subclass 16 for electric motor systems where the motor is controlled or supplied by space transmitted electromagnetic or electrostatic energy (including radio energy). 324,  Electricity: Measuring and Testing,   appropriate subclasses for systems for measuring or utilizing carrier waves. 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   appropriate subclasses for miscellaneous circuits which may constitute elements of a system such as those classifiable in this class. 333,  Wave Transmission Lines and Networks,   appropriate subclasses for passive carrier wave transmission lines which may include passive network elements, attenuators or resonators which may have utility in the carrier wave systems of this class. 340,  Communications: Electrical,   appropriate subclasses for electrical signaling systems, especially subclasses 13.2-13.36 for selective signaling systems utilizing carrier waves; subclasses 286.01 through 286.14for miscellaneous signaling systems consisting of transmitters and receivers; subclasses 539.1-539.32 for systems automatically responsive to a condition and wherein the signal is transmitted via radio levels; and subclasses 870.01-870.44 for telemetering systems. 341,  Coded Data Generation or Conversion,   appropriate subclasses for code converters and subclasses 173 through 192for code generator or transmitter. 346,  Recorders,   subclass 37 for systems wherein a recorder is operated in response to the tuning of a radio receiver or receivers, e.g., community radio listening survey. 369,  Dynamic Information Storage or Retrieval,   subclasses 6+ for combined radio and phonograph systems. 370,  Multiplex Communications,   for analog carrier wave communication systems which have multiplexing. 375,  Pulse or Digital Communications,   for systems conveying or digital pulse information which may use modulated carrier waves. 380,  Cryptography,   for cryptographic communications. 411,  Expanded, Threaded, Driven, Headed, Tool-Deformed, or Lock-Threaded Fastener,   subclasses 50+ for code converters wherein a transmitter may receive its information in the form of a first code and transmit the information in the form of a dissimilar code; and subclasses 20+ and 173+ for code transmitters.

40	Earth or water medium:
	This subclass is indented under subclass 39.  Subject matter where the ground (or water) supplies the natural medium for the transmission of the modulated carrier wave between the transmitter and receiver. (1) Note. The subject matter of this subclass has a specific under ground (or underwater) structure at each station. SEE OR SEARCH CLASS: 343,  Communications: Radio Wave Antennas,   subclass 719 for antenna systems buried underground or submerged underwater. 375,  Pulse or Digital Communications,   subclass 218 for pulse communication via an earth or water medium.

41.1	Near field (i.e., inductive or capacitive coupling):
	This subclass is indented under subclass 39.  Subject matter including a limited range system where signal transfer from the transmitter to the receiver is inductive or capacitive. SEE OR SEARCH THIS CLASS, SUBCLASS: 40, for underwater systems that may be inductive or capacitive. 41.2, for short range RF communication. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclass 43 for inductive telegraphy. 375,  Pulse or Digital Communications,   subclass 256 for near field pulse or digital communication.

41.2	Short range RF communication:
	This subclass is indented under subclass 39.  Subject matter wherein communication between transmitter and receiver is directly implemented via radio frequency signal transmission over a short, limited distance. SEE OR SEARCH THIS CLASS, SUBCLASS: 41.1, for near field inductive or capacitive coupling.

41.3	To output device:
	This subclass is indented under subclass 41.2.  Subject matter including signal transfer from the transmitter to a remote output device. (1) Note. Remote output devices may be audio speakers, printers, etc. SEE OR SEARCH THIS CLASS, SUBCLASS: 66.1, for separate transmitter and receiver with diverse art device.

42	Frequency or phase modulation:
	This subclass is indented under subclass 39.  Subject matter in which the intelligence or information to be transmitted is applied to a sine wave carrier in such a manner that the instantaneous frequency and/or phase angle of the sine wave carrier is caused to depart from a reference value by an amount proportional to the instantaneous amplitude of the modulating (intelligence) signal. SEE OR SEARCH THIS CLASS, SUBCLASS: 23, for frequency or phase modulated repeater. 29, for secret systems with carrier wobbling. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 207+ for telemetering systems utilizing frequency or phase modulation. 343,  Communications: Radio Wave Antennas,   subclass 14 for reflected wave systems utilizing pulse waves frequency or phase modulated; subclass 17.5 for reflected wave systems in general utilizing frequency or phase modulation; and subclasses 100+ for directive systems restricted to radio wave energy and utilizing frequency modulation. 359,  Optical: Systems and Elements,   various subclasses for optical communication. 375,  Pulse or Digital Communications,   subclasses 130 through 153for spread spectrum; and subclasses 223, 271, 302+, 329+, and 334+ for pulse communication by frequency or phase modulation of a carrier wave. 380,  Cryptography,   particularly subclass 322 for carrier wobbling by cryptographic equipment.

43	With modification of frequencies of analog signal passed (e.g., pre-emphasis or de-emphasis):
	This subclass is indented under subclass 42.  Subject matter where the information or modulating signal is predistorted and/or preamplified prior to its modulation of the carrier wave. SEE OR SEARCH CLASS: 332,  Modulators,   subclasses 123+ for frequency modulators, per se, with distortion introduction or control, e.g., pre-emphasis networks. 333,  Wave Transmission Lines and Networks,   subclasses 28+ for passive equalizing networks, per se.

44	With stated modulation index:
	This subclass is indented under subclass 42.  Subject matter in which the effective frequency excursion or deviation is specified.

45	Via subcarrier:
	This subclass is indented under subclass 42.  Subject matter where an intermediate frequency wave is modulated by a modulating signal representative of an intelligence or message and in turn is applied as a modulation signal to a main carrier wave, either alone or in conjunction with other subcarriers. (1) Note. The frequency of the subcarrier is usually low relative to that of the main carrier.

46	Suppressed carrier wave system:
	This subclass is indented under subclass 39.  Subject matter where the carrier component of a modulated wave is suppressed at the transmitter so that only the information bearing sideband or sidebands are transmitted and received. (1) Note. Double or single sideband, suppressed carrier systems are found here. SEE OR SEARCH THIS CLASS, SUBCLASS: 109, for suppressed carrier transmitter. 202, for suppressed carrier receivers. SEE OR SEARCH CLASS: 332,  Modulators,   subclasses 167+ for a suppressed carrier double sideband type amplitude modulator, per se.

47	Single or vestigial sideband system:
	This subclass is indented under subclass 39.  Subject matter where one sideband of the transmitted signal is largely or entirely suppressed while the second sideband has little or no suppression. (1) Note. The carrier is not suppressed. (2) Note. In this class, the term asymmetric sideband is generic to single and vestigial sideband. SEE OR SEARCH THIS CLASS, SUBCLASS: 46, for systems where the carrier is suppressed. 109, for amplitude modulated transmitters. 203, for single sideband receivers. 204, for vestigial sideband receivers. SEE OR SEARCH CLASS: 332,  Modulators,   subclasses 170+ for a single or vestigial sideband type amplitude modulator, per se. 348,  Television,   for vestigial sideband systems particular to television. 375,  Pulse or Digital Communications,   subclass 270 for similar systems for transmitting pulse data.

48	Inverted sideband:
	This subclass is indented under subclass 39.  Subject matter where one of the sidebands is shifted by 180 degrees with respect to its normal phase relationship with respect to the other sideband.

59	Single message via plural carrier wave transmission:
	This subclass is indented under subclass 39.  Subject matter where a single message or intelligence is transmitted by means of a plurality of carrier waves. (1) Note. The subject matter to be found here will include systems in which the whole intelligence signal is divided into component parts, each of the components being modulated upon a separate carrier wave or systems in which the whole undivided intelligence signal is separately modulated upon separate carrier waves. SEE OR SEARCH THIS CLASS, SUBCLASS: 13.1+, and 17, for repeaters utilizing plural channels. 27, for secret systems using a plurality of carrier waves. 42, for plural channel angle modulation systems. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclass 32 for secret telegraph systems which may employ a plurality of carrier waves or alternating current waves. 375,  Pulse or Digital Communications,   subclasses 260+ for pulse modulated carrier wave systems using plural channels to transmit a single pulse train. 380,  Cryptography,   particularly subclass 34 for a cryptographic system utilizing plural carrier frequencies.

60	Different phases of same frequency carrier:
	This subclass is indented under subclass 59.  Subject matter in which the message is modulated onto different phases (e.g., different polarizations) of a carrier wave and each phase is then separately transmitted.

61	Single message via plural modulation of single carrier:
	This subclass is indented under subclass 39.  Subject matter including modulation of a single carrier wave by a plurality of separate and distinct modulation signals each representing a portion of the intelligence to be transmitted. SEE OR SEARCH THIS CLASS, SUBCLASS: 22, for repeaters with plural conversion stages. 28, for plural modulation of a single carrier wave for secrecy. SEE OR SEARCH CLASS: 375,  Pulse or Digital Communications,   subclass 269 for pulse modulated carrier wave systems with plural modulation of a single carrier. 380,  Cryptography,   particularly subclasses 31+ for a cryptographic system utilizing plural modulation of a single carrier wave.

62	Optimum frequency selection:
	This subclass is indented under subclass 39.  Subject matter in which a frequency of operation is selected with is optimum with respect to a given criteria.

63.1	Distortion, noise, or other interference prevention, reduction, or compensation:
	This subclass is indented under subclass 39.  Subject matter with provision for reduction, compensation or elimination of an unwanted signal. SEE OR SEARCH THIS CLASS, SUBCLASS: 8, for failure compensation in a repeater. 10, for fading compensation in repeaters. 78 through 83, for transceivers with transmitter receiver interaction prevention. 119, for transmitters with carrier frequency stabilization. 134, and 135, for plural receivers with output selecting according to signal strength or quality. 222 through 224, for noise controlled squelch in a receiver. 234.1 through 253.2, for automatic gain or volume control in a receiver. 255 through 265, for local oscillator frequency control in a receiver. 267, for tone control in a receiver. 268, for fidelity control in a receiver. 278.1 through 279.1, for receiver plural wave collector noise or interference elimination. 283 through 288, for receiver wave collector interference or noise elimination. 296 through 312, for receiver noise or interference elimination. 501 through 506, for similar subject matter in plural transmitter/receiver systems. 701 through 703, for tone coded squelch.

63.2	System with hierarchical coverage areas:
	This subclass is indented under subclass 63.1.  Subject matter including interference prevention, reduction, or compensation in an hierarchical communication system which has multiple structural communication levels (e.g.,overlaid coverage areas, smaller coverage areas overlapped by larger coverage areas). SEE OR SEARCH THIS CLASS, SUBCLASS: 450, and 509, for channel allocation.

63.3	Frequency switching:
	This subclass is indented under subclass 63.1.  Subject matter including selecting between frequencies or channels to prevent interference.

63.4	Directional antenna:
	This subclass is indented under subclass 63.1.  Subject matter in which a focus beam is provided in a desired direction of transmission or reception. SEE OR SEARCH THIS CLASS, SUBCLASS: 25, for an antenna which is more responsive in one direction than another in a repeater system. SEE OR SEARCH CLASS: 342,  Communications: Directive Radio Wave Systems and Devices (e.g., Radar, and Radio Navigation),   subclasses 359 and 367 for directive system antenna orientation or a directive communication system in general, respectively.

64	Plasma source or barrier:
	This subclass is indented under subclass 63.1.  Subject matter where the distortion and noise is caused by a plasma (e.g., space craft re-entry).

65	Anti-multipath:
	This subclass is indented under subclass 63.1.  Subject matter where there is prevention, reduction, or compensation for distortion caused by the modulated carrier wave traveling from the transmitter to the receiver by plural paths of differing lengths. SEE OR SEARCH THIS CLASS, SUBCLASS: 10, for fading compensation in a repeater. 504+, for fading compensation in a plural transmitter or receiver systems.

66.1	Having diverse art device:
	This subclass is indented under subclass 39.  Subject matter including a separated transmitter and receiver system along with another art device or structure having an added purpose or independent utility other than to perfect an element of the system and in which the utility of the other art device or structure is not destroyed or disturbed by its removal from the system. (1) Note. Combination with specific art having subclass provided for in other class is classified in the other class. See search class note below. SEE OR SEARCH CLASS: 40,  Card, Picture, or Sign Exhibiting,   subclasses 455 through 457for changeable exhibitors with sound in which the source of the sound may be a radio receiver. 102,  Ammunition and Explosive,   subclass 214 for fuses utilizing a radio wave. 116,  Signals and Indicators,   subclasses 241 through 263for position indicators for radio apparatus. 178,  Telegraphy,   subclasses 118 through 120for telegraph receivers which may be combined with other art devices. 194,  Check-Actuated Control Mechanisms,   appropriate subclasses for a check controlled radio apparatus combined with other art device. 248,  Supports,   subclass 27.1 for means for supporting an instrument in a panel. 307,  Electrical Transmission or Interconnection Systems,   subclasses 9.1 through 10.8for vehicle mounted systems in which the vehicle may provide power means for a radio telephone or other receiver means and subclasses 154-157 for miscellaneous systems with particular load device or load device combination. 312,  Supports: Cabinet Structure,   subclass 7.1 for radio type cabinets. 340,  Communications: Electrical,   subclass 539 for a condition responsive indicating system with a radio coupling link. 343,  Communications: Radio Wave Antennas,   subclass 6 for reflected wave (e.g., radar) systems combined with diverse type radiant energy systems. 346,  Recorders,   subclass 25 for recorders combined with other nonrecording devices; and subclass 37 for recorders combined with a radio receiver and tuning responsive and for the purpose of determining the listening habits of the users of a receiver. 362,  Illumination,   appropriate subclasses for combined light and other art device structure. 368,  Horology: Time Measuring Systems or Devices,   subclasses 10 through 14for clocks combined with other devices where the claimed combination does not include characteristics of the device not necessary to the function of the horological device. 369,  Dynamic Information Storage or Retrieval,   subclasses 6 through 12for combined radio and phonograph systems. 386,  Motion Video Signal Processing for Recording or Reproducing,   appropriate subclasses for television or video recording and reproduction. 396,  Photography,   subclass 434 for a camera combined with a radio. 446,  Amusement Devices: Toys,   subclasses 297 through 303for a figure toy having a sounder, wherein the figure may act as a receptacle for a receiver.

67.7	With indication (e.g., visual or voice signalling, etc.):
	This subclass is indented under subclass 67.1.  Subject matter having means for making a condition pertaining to the testing or measuring of the system perceptible to a human operator. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 539.1 through 539.32for generic condition indicating system over radio link.

67.11	Having measuring, testing, or monitoring of system or part:
	This subclass is indented under subclass 39.  Subject matter which relates to means intended solely for the purpose of and adapted to (a) adjust the frequency setting of a carrier wave generation means or determine the output frequency or some other characteristics of a transmitter means; (b) adjust the frequency setting of a local oscillator, a tuning means or other stages of a receiver means in accordance with a standard frequency; c) compare the frequency of a resonant input or output circuit of a receiver or transmitter with a standard frequency for the purpose of setting a tuning position indicator or dial to correspond to maximum transmitter or receiver output at the standard frequency; and (d) determine the operating characteristics of the whole or selected components of the system under prescribed conditions of operation.

67.12	Using a chamber (e.g., room testing or audio surveillance, etc.):
	This subclass is indented under subclass 67.11.  Subject matter wherein the measuring, testing, or monitoring is conducted in a confined housing or in a relatively close location. (1) Note. For example, method or device for locating an inter-modular or interference source in a close proximity to a desired transmitting source, or detecting the presence of a hidden transmitter, e.g., eavesdropping device.

67.13	Noise, distortion, or unwanted signal detection (e.g. quality control etc.):
	This subclass is indented under subclass 67.11.  Subject matter having means to detect any undesired electrical disturbance within the useful frequency band arising from sources internal or external to the system (e.g., cross-talk, power induction, atmospheric noise, etc.), or any undesired self-sustained oscillation existing in the system, or other unwanted signals tending to interfere with the operation of the system.

67.14	Using a test signal:
	This subclass is indented under subclass 67.11.  Subject matter wherein a signal of predetermined frequency (i.e., reference signal) is sent over the system for testing or measuring purposes (e.g., emulation, loop-back, etc.).

67.15	Of a microwave link or system:
	This subclass is indented under subclass 67.11.  Subject matter involves system using communication signals in the range of microwave frequencies (i.e., approximately 1000 MHZ and above).

67.16	Phase measuring (e.g., group delay, propagation effect, etc.):
	This subclass is indented under subclass 67.11.  Subject matter including means to measure the change in phase of propagating waves. (1) Note. Phase measurement may be used for developing a suitable control for equalization, attenuation compensation, synchronization, etc.

68	With control signal:
	This subclass is indented under subclass 39.  Subject matter wherein the communication apparatus includes an intelligence signal transmitted from a transmitter to a receiver over distances large compared with their dimensions and where one of either the transmitter or receiver includes controlling means which causes some modification of the operation of the other.

69	Transmitter controlled by signal feedback from receiver:
	This subclass is indented under subclass 68.  Subject matter wherein the controlling means is located at the receiver and modifies the operation of the transmitter in response thereto.

70	Receiver control signal originates at message transmitter:
	This subclass is indented under subclass 68.  Subject matter wherein the controlling means is located at the transmitter and modifies the operation of the receiver in response to said controlling means. (1) Note. The controlling means may send a reference or controlling modulation component on the carrier wave. However, such component must be distinct from the message, as receivers responsive to the inherent characteristics of the message signal are excluded from this subclass.

71	Frequency control:
	This subclass is indented under subclass 70.  Subject matter where the frequency to which the receiver is tuned is controlled. SEE OR SEARCH THIS CLASS, SUBCLASS: 151.1, for remote control of channel or station selection in a receiver.

72	For compression and expansion of message signal (i.e., companding):
	This subclass is indented under subclass 70.  Subject matter wherein the range of variation of the modulating parameter is decreased at the transmitter and expanded in the complementary manner in the receiver. SEE OR SEARCH CLASS: 333,  Wave Transmission Lines and Networks,   subclass 14 for companding systems, per se.

73	TRANSMITTER AND RECEIVER AT SAME STATION (E.G., TRANSCEIVER):
	This subclass is indented under the class definition.  Subject matter having both a signal transmitter and a signal receiver at a common geographic location for transmission and reception of separate signals. (1) Note. The transmitter and receiver at a common location are hereafter termed "a station" in these definitions. (2) Note. The simultaneous separation of a transmitter and receiver is a duplex operation and is classified in Class 370, Multiplex Communications, subclasses 276+. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for an interference signal transmitter, which may include a receiver at the same station. 606+, for a complete light wave communication station. SEE OR SEARCH CLASS: 370,  Multiplex Communications,   subclasses 276+ for duplex systems, see (2) Note above. 375,  Pulse or Digital Communications,   subclass 219 for similar devices which handle pulse and digital signals.

74	Convertible (e.g., to diverse art device):
	This subclass is indented under subclass 73.  Subject matter wherein at least a portion of the transceiver circuitry is alternatively operable as a portion of another electrical sound signal processing system. (1) Note. The term convertible is intended to include a receiver for a different frequency band (e.g., broadcast receiver).

74.1	Cordless/corded conversion:
	This subclass is indented under subclass 74.  Subject matter wherein the transceiver includes a structure for transforming a wired transmission capability to a wireless transmission capacity or vice versa.

75	With frequency stabilization (e.g., automatic frequency control):
	This subclass is indented under subclass 73.  Subject matter having means to prevent or compensate for variation in the operating frequency of the transceiver. SEE OR SEARCH THIS CLASS, SUBCLASS: 113, and 119, for transmitter with automatic frequency control or stabilization. 164.1, 173.1, 192.1+, and 257, for receivers with automatic frequency control or stabilization. SEE OR SEARCH CLASS: 331,  Oscillators,   subclasses 1+ for oscillators with automatic frequency control.

76	Synthesizer:
	This subclass is indented under subclass 75.  Subject matter in which a single stable oscillator is used as a source of one or more frequencies derived therefrom by frequency multiplication or division. (1) Note. The stable oscillator is often crystal controlled or phase-locked. SEE OR SEARCH THIS CLASS, SUBCLASS: 165.1, and 183.1+, for receivers with synthesizers. SEE OR SEARCH CLASS: 331,  Oscillators,   subclass 1 for synthesizers in general.

77	With tuning:
	This subclass is indented under subclass 73.  Subject matter having means to control or adjust the frequency of the transmitted or received signal; or the loading or adjustment of the radio frequency circuits is varied. SEE OR SEARCH THIS CLASS, SUBCLASS: 120+, for transmitter tuning. 150.1, for receiver tuning. SEE OR SEARCH CLASS: 334,  Tuners,   for passive tuning circuits in general.

78	With transmitter-receiver switching or interaction prevention:
	This subclass is indented under subclass 73.  Subject matter wherein the transmitter and receiver are made orthogonal by alternatively actuating the transmitter or receiver or by isolation circuitry. SEE OR SEARCH CLASS: 370,  Multiplex Communications,   subclasses 278 and 282+ for transmit/receive interaction control in duplex communications.

79	Automatic (e.g., voice-operated):
	This subclass is indented under subclass 78.  Subject matter wherein the switching device is other than manually operated. (1) Note. Such means includes voice operated switching. SEE OR SEARCH THIS CLASS, SUBCLASS: 116, for transmitters automatically actuated in response to voice, etc.

80	With distributed parameter coupling:
	This subclass is indented under subclass 79.  Subject matter having a distributed parameter transmitter line coupling the transmitter and receiver portions of the transceiver to an antenna. SEE OR SEARCH CLASS: 333,  Wave Transmission Lines and Networks,   subclasses 100+ for branched circuits.

81	Waveguide:
	This subclass is indented under subclass 80.  Subject matter wherein the transmission line is a hollow conductor. SEE OR SEARCH CLASS: 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclass 593 for miscellaneous circuits with a distributed parameter element (e.g., waveguide). 333,  Wave Transmission Lines and Networks,   subclass 13 for waveguides having gas breakdown switching (e.g., T-R) tubes; subclasses 100+ for branching networks; and subclass 13 for hybrid transmit-receiver isolators.

82	Common antenna:
	This subclass is indented under subclass 79.  Subject matter where the transmitter and the receiver use the same antenna.

83	Single antenna switched between transmitter and receiver:
	This subclass is indented under subclass 78.  Subject matter which has a single antenna which is alternately connected to the transmitter and receiver. SEE OR SEARCH THIS CLASS, SUBCLASS: 82, for a single antenna automatically switched between transmitter and receiver.

84	With a common signal processing stage:
	This subclass is indented under subclass 73.  Subject matter having an active element which performs a signal processing or generating function in the transmitter portion of the apparatus during signal transmission and in the receiver portion of the apparatus during signal reception. (1) Note. The terms "active" and "signal processing" are used to exclude common use of nonprocessing elements, e.g., antennas and power supplies.

85	Transmitter oscillator used as detector:
	This subclass is indented under subclass 84.  Subject matter wherein the active element circuitry which produces the carrier signal during transmission functions as a demodulator during signal reception. (1) Note. The term demodulator used above excludes heterodyning mixers. Rather it includes only those devices producing a signal which is a replica of the original modulating information signal.

86	Transmitter oscillator used as local oscillator:
	This subclass is indented under subclass 84.  Subject matter wherein the active element circuitry which produces the carrier during transmission also produces the oscillatory signal with which the received signal is heterodyned.

87	Tunable or variable:
	This subclass is indented under subclass 86.  Subject matter where the frequency of the local oscillator is variable or changeable.

88	Transceiver controlling a separate transceiver or receiver:
	This subclass is indented under subclass 73.  Subject matter wherein the transceiver is operative to produce a signal controlling the operation of another transceiver or a receiver at the same location. (1) Note. The controlling signal may be either a signal produced for control purposes or may be the normal transmitted signal of the transceiver. (2) Note. Such control may include, for example, switching from a stand-by condition. SEE OR SEARCH THIS CLASS, SUBCLASS: 132+, for diversity-type receivers which may control one another. 352, for receivers which are remotely controlled. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 1.1 through 16.1for various remote control systems not limited to modulated carrier waves and selective paging systems.

90.1	Having particular application (e.g., avalanche victim assistance) of a transceiver:
	This subclass is indented under subclass 73.  Subject matter wherein a transceiver other than a radiotelephone is designed for or utilized in a specific environment.

90.2	Having particular configuration (e.g., C.B. or walkie-talkie) of a transceiver:
	This subclass is indented under subclass 73.  Subject matter wherein a transceiver other than a radiotelephone has a particular arrangement of its component parts. (1) Note. This includes, for example, such configurations as citizen band (CB) radio, walkie-talkie, Smart Mobile Radio (SMR), or Push To Talk (PTT).

90.3	Having particular housing or support of a transceiver:
	This subclass is indented under subclass 73.  Subject matter wherein a transceiver other than a radiotelephone has a specified enclosure or support means. SEE OR SEARCH THIS CLASS, SUBCLASS: 347, for a receiver housing. SEE OR SEARCH CLASS: 248,  Supports,   subclasses 309.1 through 316.8for bracket means for holding a radio that does not claim radio structure. 312,  Supports: Cabinet Structure,   subclass 7.1 for radio cabinets, per se, that do not claim radio structure.

91	TRANSMITTER:
	This subclass is indented under the class definition.  Subject matter comprising apparatus for generating and modulating a carrier wave and usually including the coupling of the modulated carrier wave to the transmission medium. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for an interference signal transmitter. 7+, for a repeater or relay system having a transmitter stage. 26+, for a secret system transmitter. 39+, for systems having a transmitter and a receiver. 88+, for a transceiver. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclasses 79+ for telephone transmitters. 219,  Electric Heating,   subclasses 600+ for inductive heating, subclasses 678+ for microwave heating, and subclasses 764+ for capacitive dielectric heating. 250,  Radiant Energy,   appropriate subclasses for radiant energy transmitters in general. 310,  Electrical Generator or Motor Structure,   appropriate subclasses for electrical generators. 315,  Electric Lamp and Discharge Devices: Systems,   subclass 34 for a particular electron discharge tube device in a circuit including an antenna. 322,  Electricity: Single Generator Systems,   appropriate subclasses for generating electricity. 331,  Oscillators,   appropriate subclasses. 332,  Modulators,   appropriate subclasses for modulators, per se. 340,  Communications: Electrical,   appropriate subclasses for traffic and vehicle communications; subclasses 1.1 through 16.1for selective (e.g., remote control, etc.), including subclasses 7.1-7.63 for selective paging transmitters; subclass 311.2 for nonselective paging transmitters; subclasses 539.1-539.32 for alarms with a radio link; subclasses 853.1-856.4 for well bore communications; and subclasses 870.18-870.24 for telemetering, all which may include modulated carrier waves. 343,  Communications: Radio Wave Antennas,   subclasses 5+ for reflected or returned wave systems; and subclasses 100+ for antennas which may nominally recite a transmitter. 348,  Television,   subclasses 469+ and 723+ for television transmitters. 375,  Pulse or Digital Communications,   particularly subclasses 295+ for similar transmission of pulse or digital signals. 380,  Cryptography,   appropriate subclasses for a cryptographic telecommunication system.

92	Remote control of a transmitter:
	This subclass is indented under subclass 91.  Subject matter including structure for modifying or controlling the operation of the transmitter from a point removed some distance from the transmitter. (1) Note. The controlling function may be performed automatically or manually. SEE OR SEARCH THIS CLASS, SUBCLASS: 352, for remote control of a receiver. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 12.5 , 12.51, 13.25, and 13.26 for radio remote control in selective signaling systems.

93	Convertible to different type (e.g., AM to FM):
	This subclass is indented under subclass 91.  Subject matter wherein the transmitter is constructed so that it may be changed from one type of transmitter to a different type of transmitter, such as, for example, changed from a crystal controlled to a tunable transmitter or change from FM to AM. (1) Note. If one alternative is pulse, e.g., digital transmission, the system is classified in Class 375. SEE OR SEARCH CLASS: 375,  Pulse or Digital Communications,   subclass 216 for transmitters convertible to/from pulse modulated carrier wave.

94	Alternator:
	This subclass is indented under subclass 91.  Subject matter where the transmitter power is generated by a dynamo-electric radio frequency device. SEE OR SEARCH CLASS: 178,  Telegraphy,   subclass 116 for spark gap or arc discharge transmitters.

95	Mobile or portable:
	This subclass is indented under subclass 91.  Subject matter constructed to be transportable by vehicle or person. (1) Note. The transmitters in this and the indented subclasses may be installed upon a vehicle and operated while the vehicle is in motion or may be installed or positioned on the vehicle to be ejected therefrom as in the subclass below. (2) Note. Transmitters, per se, which send signals which indicate relative direction or position are classified elsewhere. SEE OR SEARCH THIS CLASS, SUBCLASS: 11.1, for mobile or portable repeaters. 90.1 through 90.3, 517, 569.2, and 575.1-575.9, for mobile or portable transceiver. 96, for transmitter ejected from a mobile vehicle. 517+, and 575, for mobile or portable systems. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 22+ for vehicle or traffic environment signalling; and subclasses 500+ for condition responsive indicating systems. 343,  Communications: Radio Wave Antennas,   subclasses 100+ for directive type transmitters or receivers or receivers, per se.

96	Transmitter ejected from moving vehicle:
	This subclass is indented under subclass 95.  Subject matter where the transmitter is ejected from a mobile vehicle. (1) Note. The transmitter may be automatically ejected (e.g., responsive to the impact of a crash) or manually ejected by operation of a switch. SEE OR SEARCH CLASS: 244,  Aeronautics,   subclasses 138+ for safety lowering devices in general of the aeronautical type. 340,  Communications: Electrical,   subclasses 22+ for vehicle or traffic environment signalling. 343,  Communications: Radio Wave Antennas,   subclasses 100+ for sending of radio wave energy which is characterized by relative direction or position and is not ejected or activated by a moving vehicle.

97	With antenna ejection or external support:
	This subclass is indented under subclass 95.  Subject matter including provision for ejecting or extending an antenna from the transmitter, or having provision for externally supporting an antenna (e.g., a balloon). (1) Note. The antenna ejection or antenna support may or may not be automatically operated.

98	With aircraft, satellite, or projectile:
	This subclass is indented under subclass 95.  Subject matter combined with or carried by an air or space vehicle. SEE OR SEARCH THIS CLASS, SUBCLASS: 96, if the transmitter is ejected from the vehicle.

99	With vehicle:
	This subclass is indented under subclass 95.  Subject matter carried by or combined with a vehicle such as surface craft, submarine, automobile, or other land or waterborne vehicle. SEE OR SEARCH THIS CLASS, SUBCLASS: 98, for transmitters combined with aircraft. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 22+ for vehicle or traffic environment signalling. 343,  Communications: Radio Wave Antennas,   subclasses 709 and 710 for waterborne antennas. 441,  Buoys, Rafts, and Aquatic Devices,   subclass 89 for body attached buoyant devices combined with analog modulated carrier wave communications.

100	Body attached or connected:
	This subclass is indented under subclass 95.  Subject matter which is shaped to fit the body or be supported by the body. (1) Note. For classification in this subclass, a portion of the transmitter must be shaped to fit or be supported by the body such as an antenna or microphone attached to the body. Small hand carried transmitters with no portion thereof connected to the body are classified elsewhere in this class. SEE OR SEARCH THIS CLASS, SUBCLASS: 95, for small hand carried transmitters with no portion thereof connected to the body. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 573.1+ for transmitters responsive to the condition of a human which may be attached or connected to the body. 343,  Communications: Radio Wave Antennas,   subclass 718 for body attached or supported antennas.

101	Diversity:
	This subclass is indented under subclass 91.  Subject matter where two or more channels are transmitted via different paths, frequencies, or times of transmission. (1) Note. Subject matter classified here is distinguished from multiplex, Class 370, in that no specialized receiver is needed for discerning the separate channels. (2) Note. Subject matter classified here is limited to the transmission of a single message at a time over the channels. (3) Note. Some system classified here are directed toward reducing fading at the receiver.

102	Plural modulation:
	This subclass is indented under subclass 91.  Subject matter in which the carrier wave is modulated at least twice prior to transmission. (1) Note. The plural modulation may be of the same or diverse types, and is usually sequential. SEE OR SEARCH CLASS: 332,  Modulators,   subclasses 119+ , 145 and 151+ for plural modulation, per se.

103	Plural separate transmitters or channels:
	This subclass is indented under subclass 91.  Subject matter where there are plural transmission channels formed of separate complete transmitters, capable of independent operation. (1) Note. The plural transmitters may be interconnected to a common antenna, by a common power supply or by a common control signal path. (2) Note. Systems using multiplex techniques to combine separate messages and apply to a common antenna are classified in Class 370, subclasses 339+.

104	Carrier and sidebands separately transmitted:
	This subclass is indented under subclass 103.  Subject matter where separate channels are provided for transmitting the carrier and the sideband components of a modulated carrier wave. (1) Note. Also included in this subclass are transmitters having separate channels for the carrier and sideband components and with means to produce a rotating field pattern.

105	Common frequency:
	This subclass is indented under subclass 103.  Subject matter where the plural transmitters broadcast on the same frequency. (1) Note. Systems with frequency control of the second, spaced, or remote, transmitter are classified in subclass 92 above.

106	Modulation by absorption, shielding, or reflecting:
	This subclass is indented under subclass 91.  Subject matter including structure spaced from or external to the antenna which modulates the carrier radiated from the antenna, such as by absorption, shielding, or reflecting. (1) Note. The radiated carrier may be angle modulated or it may be amplitude modulated. SEE OR SEARCH THIS CLASS, SUBCLASS: 121+, and 129+, for systems not limited to modulation systems. SEE OR SEARCH CLASS: 343,  Communications: Radio Wave Antennas,   subclasses 753+ for radio antennas with external radio wave refractor.

107	With variation of antenna impedance or dimension for modulation:
	This subclass is indented under subclass 91.  Subject matter where the carrier wave is modulated, under control of the modulating intelligence signal, by varying the impedance or dimension of the antenna. SEE OR SEARCH THIS CLASS, SUBCLASS: 121+, for systems in which the antenna circuit is varied for tuning. 129+, for systems in which the antenna coupling is explicitly shown and varied therefor. 269+, for systems of antenna combined with receiver for similar coupling arrangements, noting especially 289.

108	Amplitude modulation:
	This subclass is indented under subclass 91.  Subject matter where the amplitude of the carrier is varied under control of the intelligence to be transmitted.

109	Vestigial or single sideband or suppressed carrier:
	This subclass is indented under subclass 108.  Subject matter where less than two complete sidebands are transmitted, with or without the carrier or two complete sidebands are transmitted without the carrier. SEE OR SEARCH THIS CLASS, SUBCLASS: 46, for suppressed carrier wave systems. 47, for single or vestigial sideband systems. SEE OR SEARCH CLASS: 332,  Modulators,   subclasses 167+ for a suppressed carrier double sideband type amplitude modulator. 348,  Television,   subclasses 723+ for vestigial sideband television transmitters.

110	Angle modulation:
	This subclass is indented under subclass 91.  Subject matter where the frequency or phase of the carrier wave is varied or modulated under control of the intelligence that is transmitted.

111	Including distributed parameter structure:
	This subclass is indented under subclass 110.  Subject matter including, as a significant part of the transmitter, a structure with distributed parameter wave transmission means or circuits designed to simulate the impedance characteristics of distributed parameter wave transmission means. SEE OR SEARCH CLASS: 333,  Wave Transmission Lines and Networks,   appropriate subclasses for distributed electric parameter devices, per se.

112	With frequency multiplication or division:
	This subclass is indented under subclass 110.  Subject matter where a signal at one frequency is converted to a second frequency which is a multiple or sub-multiple of the first frequency. SEE OR SEARCH CLASS: 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 113+ for miscellaneous frequency conversion or control. 363,  Electric Power Conversion Systems,   subclasses 157+ for power frequency conversion.

113	With frequency control:
	This subclass is indented under subclass 110.  Subject matter where the operating frequency of the transmitter is controlled or regulated.

114.1	Having harmonic radiation suppression:
	This subclass is indented under subclass 91.  Subject matter having provision for the reduction or suppression of a sinusoidal wave having a frequency which is an integral multiple of a fundamental frequency at an antenna.

114.2	Noise or interference elimination:
	This subclass is indented under subclass 91.  Subject matter having structure to suppress the influence of extraneous electric fields upon transmitter circuitry.

114.3	Predistortion (e.g., for power amplifier):
	This subclass is indented under subclass 114.2.  Subject matter where a transmitted signal may prior to transmission, be distorted in a manner complementary to the distortion introduced in the power amplifier, antenna or transmission medium, etc. SEE OR SEARCH CLASS: 375,  Pulse or Digital Communications,   subclasses 296 through 297for predistortion techniques in the transmission of pulse or digital signals.

115.1	Measuring, testing, or monitoring of transmitter:
	This subclass is indented under subclass 91.  Subject matter having measuring, testing, or monitoring of the signals transmitted. (1) Note. The transmitter must be claimed in detail along with the monitoring means, claimed broadly or in detail. SEE OR SEARCH CLASS: 324,  Electricity: Measuring and Testing,   subclasses 76.11 through 157for measuring sensing or testing electricity, per se. 340,  Communications: Electrical,   subclass 653 for condition of electronic circuit or component responsive indication.

115.2	Using a test signal:
	This subclass is indented under subclass 115.1.  Subject matter wherein a signal of predetermined frequency (i.e., reference signal) is involved in the process of testing or measuring.

115.3	Signal strength:
	This subclass is indented under subclass 115.1.  Subject matter including a means for measuring a signal intensity level.

115.4	Having meter or indicator:
	This subclass is indented under subclass 115.1.  Subject matter including a means for displaying to a human observer information concerning a transmitter characteristic being measured.

116	Carrier amplitude control (e.g., voice operated on/off):
	This subclass is indented under subclass 91.  Subject matter where the amplitude of the carrier signal is controlled responsive to the modulation signal. (1) Note. For classification in this subclass the amplitude of the carrier is varied responsive to the modulation signal, for example, the carrier amplitude is reduced or cut off when the modulating signal is absent or reduced.

117	With electrical protection of transmitter circuit or operator:
	This subclass is indented under subclass 91.  Subject matter where the transmitter circuits or operators are protected from damage or injury such as from overload or malfunction of a component within the transmitter. (1) Note. For classification in this subclass some detail of the transmitter must be claimed along with the protective means, claimed broadly or in detail, for protecting the operator or transmitter. Where the transmitter is claimed broadly (such as by name only) and the protective means is claimed in detail, classification is with the protective means. (2) Note. The overload may be the result of a defective tube or other component within the transmitter or it may be the result of an external fault such as an antenna failure, lightning, or of transmission line arc-over. (3) Note. Transmitters with temperature modifier or control means, such, for example, as cooling are in this subclass. (4) Note. Transmitters with automatic condition responsive alarm are elsewhere in this class. (5) Note. Operator protection is also included here. SEE OR SEARCH THIS CLASS, SUBCLASS: 115.1 through 115.4, for transmitters with automatic condition responsive alarm. SEE OR SEARCH CLASS: 307,  Electrical Transmission or Interconnection Systems,   subclasses 326+ for generic personnel safety means. 330,  Amplifiers,   subclass 51 for amplifiers with automatic disabling switch. 331,  Oscillators,   subclass 62 for oscillators with circuit means. 361,  Electricity: Electrical Systems and Devices,   subclasses 1+ for safety and protection of electrical systems and devices.

118	Frequency conversion:
	This subclass is indented under subclass 91.  Subject matter where a signal is converted from a first frequency to a second frequency. SEE OR SEARCH CLASS: 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 113+ for miscellaneous frequency conversion or control. 331,  Oscillators,   subclasses 51 and 53 for plural oscillator frequency multipliers and dividers. 363,  Electric Power Conversion Systems,   subclasses 157+ for electric power frequency conversion.

119	Carrier frequency stabilization:
	This subclass is indented under subclass 91.  Subject matter including provision to prevent or compensate for undesirable drift or change in the frequency at which the transmitter is operating. (1) Note. The prevention or compensation for the drift or change in frequency of the transmitter may be automatically controlled.

120	Including tuning:
	This subclass is indented under subclass 91.  Subject matter including a resonant network or crystal whose resonant frequency may be varied (tuned) to control or modify the operating frequency of the transmitter, or which may be substituted for other resonant networks or crystals, as by switching, to control or modify the operating frequency of the transmitter.

121	In antenna circuit:
	This subclass is indented under subclass 120.  Subject matter wherein the tuning structure or circuitry is located within the antenna or forms part of the antenna coupling circuit. SEE OR SEARCH THIS CLASS, SUBCLASS: 129, for a transmitter with an antenna circuit with variable coupling thereto.

122	With saturable reactor:
	This subclass is indented under subclass 121.  Subject matter having a magnetic core reactor which is controlled by adjusting a superimposed unidirectional magnetic flux to effect adjustment of saturation of the core. SEE OR SEARCH CLASS: 307,  Electrical Transmission or Interconnection Systems,   subclasses 401+ for saturable reactor systems, in general.

123	Automatically controlled:
	This subclass is indented under subclass 121.  Subject matter wherein the tuning is controlled in response to a signal condition.

124	Distributed parameter device:
	This subclass is indented under subclass 120.  Subject matter where the tuning structure includes, as a significant part thereof, structure with distributed parameter wave transmission circuits or circuits designed to simulate the impedance characteristics of distributed parameter wave transmission circuits. SEE OR SEARCH CLASS: 333,  Wave Transmission Lines and Networks,   appropriate subclasses.

125	Automatic adjustment of tuning:
	This subclass is indented under subclass 120.  Subject matter where the variation or substitution is in response to a characteristic of the transmitter or transmitted signal.

126	With feedback of modulated output signal:
	This subclass is indented under subclass 91.  Subject matter including provision to apply a portion of the output signal of the transmitter to the input of a prior stage. (1) Note. The feedback circuit may include an auxiliary pickup coil or antenna to collect a portion of the energy being transmitted. (2) Note. The signal feedback may be shifted in phase to compensate for hum or distortion. SEE OR SEARCH THIS CLASS, SUBCLASS: 69, for a system having a transmitter and receiver at separate stations in which the transmitter is controlled by signal feedback from the receiver.

127.1	Power control, power supply, or bias voltage supply:
	This subclass is indented under subclass 91.  Subject matter including control detail of transmitter power output (e.g., via power amplifiers), or detail of the source of electrical energy, or of the circuitry connecting such source to the transmitter for supplying power, or biasing potential to the active elements of the transmitter. SEE OR SEARCH THIS CLASS, SUBCLASS: 117, for power or bias control for transmitter circuit or operator protection. 343, for power or bias voltage supply in receivers. 572, for power supply in transceiver.

127.2	Gain control:
	This subclass is indented under subclass 127.1.  Subject matter including detail of controlling the gain of an active element (such as power amplifier) of the transmitter. SEE OR SEARCH CLASS: 330,  Amplifiers,   subclass 278 for gain control means.

127.3	Plural amplifier stages:
	This subclass is indented under subclass 127.2.  Subject matter including detail of controlling the gains of plural amplifier stages of the transmitter. SEE OR SEARCH CLASS: 330,  Amplifiers,   appropriate subclasses for amplifiers, per se.

127.4	Dual mode (e.g., analog and digital):
	This subclass is indented under subclass 127.1.  Subject matter including detail of a transmitter operable in either of two modes. SEE OR SEARCH THIS CLASS, SUBCLASS: 553.1, for dual mode radiotelephone using more than one transceiver (e.g., for analog and digital, trunking and cellular, etc.).

127.5	Power conservation:
	This subclass is indented under subclass 127.1.  Subject matter including detail of reducing power consumption in a transmitter. SEE OR SEARCH THIS CLASS, SUBCLASS: 574, for power conservation in transceiver. SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclass 7.32 for battery saving in code responsive receiver (such as pager). 713,  Electrical Computers and Digital Processing Systems: Support,   subclasses 320 through 324for computer power conservation.

128	With casing or housing:
	This subclass is indented under subclass 91.  Subject matter provided with a casing or housing for enclosing the transmitter or a portion of the transmitter. (1) Note. For classification in this subclass, some detail of the transmitter must be claimed along with the casing or housing. SEE OR SEARCH CLASS: 174,  Electricity: Conductors and Insulators,   subclasses 50 through 565for electrical equipment boxes and housings, in general. 220,  Receptacles,   appropriate subclasses. 312,  Supports: Cabinet Structure,   subclass 7.1 for radio cabinets, per se. 331,  Oscillators,   subclasses 67 through 69for oscillators with shielding, casings, or housings. 361,  Electricity: Electrical Systems and Devices,   subclasses 331+ for housings and mounting assemblies with plural diverse electrical components.

129	With coupled antenna:
	This subclass is indented under subclass 91.  Subject matter including an antenna and circuit for coupling the antenna to the active elements of the transmitter. (1) Note. For classification here, some transmitter details should be included in the claimed combination. Combinations of antenna, coupling, and nominal transmitter are classified in Class 343, Communications: Radio Wave, subclasses 850+. See also (4) Note under subclass 850 of Class 343. SEE OR SEARCH THIS CLASS, SUBCLASS: 114.1 through 114.3, for coupling systems restricted or related to suppression of harmonics.

130	RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER:
	This subclass is indented under the class definition.  Apparatus comprising (a) means for receiving a carrier wave, upon which an information signal has been modulated, and deriving the original information signal from the modulated carrier wave. Further means may be provided for converting the derived signal into a physical manifestation readily perceived by at least one of the human senses (e.g., sound) or (b) devices whereby an incoming carrier wave signal, which has been modulated by an analog signal, is changed from one carrier frequency to another carrier frequency. (1) Note. The system and apparatus found in this and the indented subclasses under (1) above will include wave collection means, at least one wave mixing or modifying means, detector, or demodulator means and utilization means, which utilization means may consist of a sound reproducing device. This class also contains subcombinations of any of the above recited elements combined with coupling circuitry, whereby some function of a complete receiver system is performed; as for example, antenna means broadly plus detector, radio frequency amplifier plus mixer means, etc., and which subcombinations are not elsewhere classifiable. (2) Note. The apparatus found in this and the indented subclasses will be restricted to those systems which are limited, by claimed subject matter, to use in the reception and utilization of electromagnetic wave energy transmitted in the form of a carrier wave having an analog signal of arbitrary message content modulated thereon or in the form of one or more sidebands, with or without a carrier, resulting from the modulation of a carrier wave by some external source. The modulation may consist of amplitude modulation, frequency, or phase modulation, or any combination thereof. The utilization means will in general comprise loud speaker means but may include visual reproduction means or in some cases a combination of both. (3) Note. Ordinarily this and the indented subclasses will not include patents whose claimed subject matter includes (a) devices for the operation and control of mechanical devices at a distance by radiant energy, (b) systems and devices for the reception and utilization of facsimile (television) or telegraph signals, (c) systems and devices for the reception of energy which utilize compressional waves in the audible range (telephony), (d) systems and apparatus restricted to the use of radio wave energy which is transmitted to and reflected from some object, the reflected energy being received at a receiving station (i.e., radar), and (e) systems and apparatus for the communication of pulse or digital information. SEE OR SEARCH CLASS: 74,  Machine Element or Mechanism,   subclasses 10+ for mechanical dial operators; and see the notes thereto for the electrical type. 178,  Telegraphy,   and 379, Telephonic Communications, appropriate subclasses for line instruments restricted to use in these arts, particularly Class 178, subclasses 15 , 17, 48, and 88+ for receivers and recorders adapted to code-signalling. 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 113+ for miscellaneous frequency conversion or control. 329,  Demodulators,   appropriate subclasses for demodulators in general and particularly subclasses 315+ for frequency demodulators, subclasses 345+ for phase demodulators, and subclasses 347+ for amplitude demodulators. 330,  Amplifiers,   appropriate subclasses for radio frequency, intermediate frequency, or audio frequency amplifiers, per se, useful in receivers in this class. 331,  Oscillators,   appropriate subclasses for electrical oscillator systems of general application, particularly subclasses 1+ for automatic frequency stabilized oscillators; and subclasses 37+ for beat frequency oscillators similar to the frequency conversion stage of a heterodyne type receiver. 334,  Tuners,   appropriate subclasses for specific adjustable resonant circuits, per se, utilizable as tuners for radio receivers. 343,  Communications: Radio Wave Antennas,   subclasses 5+ for reflected or otherwise returned wave systems, e.g., radar; and subclasses 100+ for directive radio wave energy systems including receivers; see subclass 113 for direction finding receivers; and subclasses 700+ for antennas which may be used with radio receivers. 370,  Multiplex Communications,   for modulated carrier wave receivers and systems designed to simultaneously receive a plurality of messages. 375,  Pulse or Digital Communications,   subclasses 316+ for pulse and digital modulated carrier wave receivers. 398,  Optical Communications,   various subclasses for optical communication. 714,  Error Detection/Correction and Fault Detection/Recovery,   subclasses 712+ for diagnostic test of transmission facility.

131	Frequency conversion between signal source (e.g., wave collector) and receiver:
	This subclass is indented under subclass 130.  Subject matter where the frequency of the signal supplied by the signal source (antenna or cable) is converted to another frequency which the receiver is able to receive.

132	Plural receivers:
	This subclass is indented under subclass 130.  Subject matter which comprises all of the essential elements (as defined in the definition of subclass 130 above and not merely by name only) of two or more separate receiver means, each of the receiver means being capable of, if detached from or removed from each of the other separate receivers, deriving a useful signal which is representative of useful information carried by an incoming modulated carrier wave and which plural receiver system is not otherwise classifiable. (1) Note. The subject matter found here may include a plurality of structurally claimed receiver means whose input is derived from separate antenna or collector means, or a plurality of receiver means having some stage in common; for example, a common local oscillator, volume control, or utilization means, provided, that each recited receiver means is capable, if acting along and utilizing the common stage, of deriving a signal representative of the useful information carried by the modulation signal. Systems wherein a plurality of individual receiver means are fed from a single antenna will not be found here but in subclasses 6.1+. For purposes of classification in this subclass a plurality of receivers each receiving its input from a single source are considered to be merely a plurality of output channels for a single carrier wave input even though each of the channels performs the normal function of a complete receiver having a common input means and may be tuned to receive a different wave frequency. (2) Note. The plurality of receivers found in this and the indented subclasses will generally be located at the same geographical location (as in a rack) or closely adjacent thereto (as in a building or structure), for example, plural nondirectional receivers utilized in a diversity system. The antennas or collecting means may be situated at some distance apart, but in the same general vicinity. To be classified here the plurality of receivers must have some common cooperation or association one with another. For a plurality of receivers located at distant locations relative to each other even though they may be responsive to a particular carrier wave originating at single transmitter the search must be extended to the systems subclasses herein-above in this class or other appropriate classes.

133	With output selecting:
	This subclass is indented under subclass 132.  Subject matter where output signals from the several receivers are compared and a selected one of the output signals is either (a) applied to a utilization means, or (b) suppressed or prevented from appearing at the utilization means.

134	By signal strength:
	This subclass is indented under subclass 133.  Subject matter where the output signal is selected according to its amplitude.

135	By signal quality (e.g., signal to noise ratio):
	This subclass is indented under subclass 133.  Subject matter where the output signals are selected according to a measure of their signal quality.

136	With control (e.g., automatic gain control, automatic frequency control, etc.):
	This subclass is indented under subclass 133.  Subject matter having provision for controlling an operating characteristic of at least one of the receivers.

137	With output combining:
	This subclass is indented under subclass 132.  Subject matter where the outputs of two or more of the receivers are combined in an additive manner before being applied to a common utilization means.

138	With control (e.g., automatic gas control):
	This subclass is indented under subclass 137.  Subject matter where one or more of the operating characteristics of one or more of the receivers is controlled.

139	Frequency or phase control:
	This subclass is indented under subclass 138.  Subject matter where the frequency or phase of an oscillator in the receiver is controlled.

140	Selectively actuated or controlled:
	This subclass is indented under subclass 132.  Subject matter where each of the separate receivers may be independently energized, connected to a signal such as an antenna, individually tuned, or otherwise controlled to the exclusion of the others.

141	Including common stage (e.g., local oscillator):
	This subclass is indented under subclass 132.  Subject matter including one or more local oscillators or other stage which act in common with two or more of the receivers.

142	Convertible to different type (e.g., AM to FM):
	This subclass is indented under subclass 130.  Subject matter comprising a receiver whose circuit can be changed to receive at least two different types of modulation, for example, amplitude or frequency modulated waves. (1) Note. Such receivers may be of the superheterodyne type and employ a common pre-amplifier, converter, and intermediate frequency stage for both types of modulation. SEE OR SEARCH CLASS: 370,  Multiplex Communications,   appropriate subclasses for digital combined with analog transmission. 375,  Pulse or Digital Communications,   subclass 216 for digital convertible to/from analog.

143	With distinct signal path for each type:
	This subclass is indented under subclass 142.  Subject matter where the receiver contains a plurality of separate signal paths, each path being adapted for a different type of modulated signal, between the input and the output of receiver. (1) Note. An example of the subject matter found here may include separate diverse type collection means followed by a radio frequency stage or stages and a mixer with a common intermediate frequency stage followed by diverse detectors feeding a common audio frequency amplifier.

144	With dual purpose amplifying or other stage:
	This subclass is indented under subclass 142.  Subject matter including one or more stages which perform plural functions. (1) Note. Some examples of dual purpose stages are VHF an UHF amplifiers, amplifier and limiter, and AM-FM detector.

145	Panoramic display:
	This subclass is indented under subclass 130.  Subject matter including a cathode-ray oscilloscope for displaying the received signals. SEE OR SEARCH THIS CLASS, SUBCLASS: 1, for transmitters controlled by a spectrum sweeping or panoramic type receiver for transmitting a jamming signal. SEE OR SEARCH CLASS: 324,  Electricity: Measuring and Testing,   subclasses 76.12+ for apparatus for the analysis of complex electrical waves and which utilize panoramic display methods. 329,  Demodulators,   appropriate subclasses for a demodulator including a cathode-ray tube. 343,  Communications: Radio Wave Antennas,   subclasses 100+ for directive radio wave energy panoramic-type receivers utilized as radio beacons.

146	Plural separate paths or plural oscillators:
	This subclass is indented under subclass 145.  Subject matter wherein the receiver includes more than one individual circuit path or more than one local oscillator. (1) Note. For plural separator signal paths, at least a portion of the input carrier wave is conducted to an output utilization means by each path. (2) Note. For plural oscillators, the output of each oscillator is applied to one of a plurality of mixer or conversion means. SEE OR SEARCH THIS CLASS, SUBCLASS: 143, 303+ and 313, for other types of receivers having plural signal paths therein. 315+, for plural frequency conversion means with plural local oscillators.

147	Particular local oscillator control:
	This subclass is indented under subclass 145.  Subject matter wherein the receiver includes particular means whereby the frequency of the local oscillator means is maintained constant or whereby some other operating condition of the oscillator means is controlled. SEE OR SEARCH THIS CLASS, SUBCLASS: 164.1, for scanning receivers with automatic frequency control. 173.1, for mechanical or electromechanical frequency selection means with automatic frequency control. 182.1, for channel or station selection with automatic frequency control. 208+, for frequency or phase modulation type receivers with synchronized or controlled local oscillator means. 255+, for automatic frequency control systems for receivers in general. 316, for receivers with frequency conversion means with frequency stabilizing means for the local oscillator.

148	With oscilloscope sweep signal derivation or control:
	This subclass is indented under subclass 145.  Subject matter wherein the receiver includes particular means for generating or controlling the voltage applied to the oscilloscope (e.g., control of voltage amplitude or cathode-ray beam intensity). SEE OR SEARCH CLASS: 315,  Electric Lamp and Discharge Devices: Systems,   subclasses 364+ for cathode-ray tube deflection systems in general, particularly subclasses 383+ for ray beam intensity control. 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 131+ for miscellaneous sawtooth or ramp circuit. 331,  Oscillators,   subclasses 143+ for free running relaxation oscillators utilized as sawtooth generators.

149	Plural output (e.g., plural speakers) (not stereo):
	This subclass is indented under subclass 130.  Subject matter where the receiver has a plurality of separate outputs. (1) Note. Stereo receivers are classified in Class 381, subclasses 1+.

150.1	Signal selection based on frequency (e.g., tuning):
	This subclass is indented under subclass 130.  Subject matter comprising means to cause the receiver to respond, selectively, to any one of two or more carrier waves. SEE OR SEARCH THIS CLASS, SUBCLASS: 77, for transceivers tuning. 120+, for transmitters with tuning. 340, for receivers in general with adjustable tuning means between stages. SEE OR SEARCH CLASS: 74,  Machine Element or Mechanism,   subclasses 10+ for a radio tuner by names only when claimed in combination with shaft positioning means. 324,  Electricity: Measuring and Testing,   subclasses 76.39+ for systems for measuring the frequency of a cyclic current or voltage by tuning to resonance with a reference source. 327,  Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,   subclasses 1+ for miscellaneous discriminating circuits and particularly subclasses 39+ for frequency discrimination. 334,  Tuners,   appropriate subclasses for tuners, per se. 336,  Inductor Devices,   appropriate subclass for specific type inductor, per se, which may be used in a selective circuit, see particularly subclasses 130+ . 340,  Communications: Electrical,   subclasses 870.4+ for telemetering systems including selective receivers. 342,  Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),   subclasses 5+ for radar receivers with wave selecting means and subclasses 100+ for directive receivers with selecting means. 346,  Recorders,   subclass 37 for the combination of a tuning responsive radio receiver with recording means. 348,  Television,   subclasses 725+ for television receivers having frequency selecting means. 361,  Electricity: Electrical Systems and Devices,   subclasses 182+ for electric control circuits for relays which are frequency responsive. 370,  Multiplex Communications,   appropriate subclass for multiplex receivers with frequency selection means. 375,  Pulse or Digital Communications,   subclasses 316+ for pulse receivers with frequency selection.

151.1	Remote control of channel or station selection:
	This subclass is indented under subclass 150.1.  Subject matter wherein the tuning means includes a control means that is actuated at a distance from the receiver. SEE OR SEARCH THIS CLASS, SUBCLASS: 352+, for remote control of receivers for other than signal selection. SEE OR SEARCH CLASS: 334,  Tuners,   subclasses 8+ for remotely controlled tuner which claims significant details of the tuner.

151.2	Wireless link (sonic, RF or infrared):
	This subclass is indented under subclass 151.1.  Subject matter wherein the remote control device is not physically connected to the receiver and generates an acoustic wave, an electromagnetic wave, or a pulse train (e.g., sonic, RF, or infrared). SEE OR SEARCH CLASS: 340,  Communications: Electrical,   subclasses 2.1 through 2.8for path selection.