*****TBD*****

This subclass is indented under the class definition. Subject matter where the demodulator extracts the modulating signal from a signal which has undergone frequency shift keying modulation or minimum shift keying modulation.

(1) Note. Frequency shift keying modulation occurs when the frequency of a carrier is shifted among a plurality of discrete values in accordance with the modulating signal.

(2) Note. Minimum shift keying modulation is a type of frequency shift keying modulation in which there is phase continuity at the frequency transition points.

(3) Note. This subclass includes frequency shift keying demodulators, per se. See the SEARCH CLASS notes below for combinations with the subject matter of this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

304+,

for a phase shift keying demodulator.

SEE OR SEARCH CLASS:

375,	Pulse or Digital Communications, subclasses 272+ for a frequency shift keying system (i.e., transmitter and receiver) and subclasses 322+ for a frequency shift keying demodulator combined with receiving structure.

301	. Including discrete semiconductor device:

This subclass is indented under subclass 300. Subject matter containing an electrical device whose constituent portions are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

302	. Input signal combined with local oscillator or carrier frequency signal:

This subclass is indented under subclass 300. Subject matter where the modulated signal input to the demodulator interacts with oscillations from a secondary source.

(1) Note. The secondary oscillations may be internally generated or externally supplied and may be at a frequency other than that of the modulated input signal"s carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:

306+,	for similar structure in a phase shift keying or quadrature amplitude demodulator.
323+,	for similar structure in a frequency modulation demodulator.
346,	for similar structure in a phase modulation demodulator.
358+,	for similar structure in an amplitude modulation demodulator.

303	. Including logic element (e.g., logic gate or flip-flop):

This subclass is indented under subclass 300. Subject matter containing a component which performs a Boolean Algebraic operation.

(1) Note. Such components may be combinational or sequential (e.g., AND gates, OR gates or J-K flip-flops).

304	PHASE SHIFT KEYING OR QUADRATURE AMPLITUDE DEMODULATOR:

This subclass is indented under the class definition. Subject matter where the demodulator extracts the modulating signal from a signal which has undergone phase shift keying modulation or quadrature amplitude modulation.

(1) Note. Phase shift keying modulation occurs when the phase of a carrier is shifted among a plurality of discrete angles in accordance with the modulating signal.

(2) Note. Quadrature amplitude modulation occurs when the phase and amplitude of a carrier is simultaneously shifted among a plurality of discrete angle/magnitude pairs.

(3) Note. This subclass includes phase shift keying demodulators or quadrature amplitude demodulators, per se. See the SEARCH CLASS notes below for combinations with the subject matter of this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

300+,

for a frequency shift keying demodulator.

SEE OR SEARCH CLASS:

375,	Pulse or Digital Communications, subclass 261 for a quadrature amplitude modulation system (i.e., transmitter and receiver), subclasses 279+ for a phase shift keying system, and subclasses 322+ for a phase shift keying demodulator combined with receiving structure.

305	. Including discrete semiconductor device:

This subclass is indented under subclass 304. Subject matter containing an electrical device whose constituent portions are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

306	. Input signal combined with local oscillator or carrier frequency signal:

This subclass is indented under subclass 304. Subject matter where the modulated signal input to the demodulator interacts therein with oscillations from a secondary source.

(1) Note. The secondary oscillations may be internally generated or externally supplied and may be at a frequency other than that of the modulated input signal"s carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:

302,	for similar structure in a frequency shift keying or minimum shift keying demodulator.
323+,	for similar structure in a frequency modulation demodulator.
346,	for similar structure in a phase modulation demodulator.
358+,	for similar structure in an amplitude modulation demodulator.

307	.. Including phase or frequency locked loop:

This subclass is indented under subclass 306. Subject matter in which a phase or frequency locked loop provides stability to or synchronization with the secondary source of oscillations.

SEE OR SEARCH CLASS:

331,	Oscillators, subclasses 1+ for phase or frequency locked loops, per se.
375,	Pulse or Digital Communications, subclass 327 and 376 for phase locked loops in digital receivers or synchronizers, respectively.

308	... With parallel signal combiners (e.g., costas loop):

	This subclass is indented under subclass 307. Subject matter utilizing a plurality of signal combiners where the modulated input signal is combined with relatively phase shifted versions of the secondary oscillations, or where the secondary oscillations are combined with relatively phase shifted versions of the modulated input signal.

309	.... Including logic element (e.g., logic gate or flip-flop):

This subclass is indented under subclass 308. Subject matter containing a component which performs a Boolean Algebraic operation.

(1) Note. Such components may be combinational or sequential (e.g., AND gates, OR gates or J-K flip-flops).

310	. Including logic element (e.g., logic gate or flip-flop):

This subclass is indented under subclass 304. Subject matter containing a component which performs a Boolean Algebraic operation.

(1) Note. Such components may be combinational or sequential (e.g., AND gates, OR gates or J-K flip-flops).

311	PULSE OR INTERRUPTED CONTINUOUS WAVE DEMODULATOR:

This subclass is indented under the class definition. Subject matter where the demodulator extracts the modulating signal from a modulated signal which has undergone pulse modulation.

(1) Note. Pulse modulation occurs when a repetitious pulse wave has a characteristic varied in accordance with the modulating signal.

(2) Note. Interrupted continuous wave modulation occurs when a pulsed continuous wave has a characteristic varied in accordance with the modulating signal.

(3) Note. Examples of pulse waves are square waves, sawtooth waves, and trapezoidal waves.

(4) Note. Comparable structure having an input which is pulse code modulated (PCM) or delta modulated are found elsewhere. See the Search Notes below.

(5) Note. This subclass includes pulse demodulators, per se. See the SEARCH CLASS notes below for combinations with the subject matter of this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

315+,	for a frequency modulation demodulator.
341+,	for an FM demodulator which initially transforms the input signal into pulses.
345+,	for a phase modulation demodulator.
347+,	for an amplitude modulation demodulator.

SEE OR SEARCH CLASS:

341,	Coded Data Generation or Conversion, subclasses 126+ or 143 for a structure comparable structure to this subclass (311) having an input which is pulse code modulated (PCM) or delta modulated.
375,	Pulse or Digital Communications, appropriate subclasses, for combinations of a pulse demodulator with receiving structure.

312	. Pulse width demodulator:

This subclass is indented under subclass 311. Subject matter where the modulated signal input to the demodulator has undergone pulse width modulation.

(1) Note. Pulse width modulation is a form of pulse modulation in which the width (duration) of the pulses is the characteristic that is varied.

SEE OR SEARCH CLASS:

375,	Pulse or Digital Communications, subclass 238 or 340+ for a combination of pulse width demodulator with receiving structure.

313	. Pulse position, frequency, phase or spacing demodulator:

This subclass is indented under subclass 311. Subject matter where the modulated signal input to the demodulator has undergone pulse position, frequency, phase or spacing modulation.

(1) Note. Pulse position, frequency, phase or spacing modulation are forms of pulse modulation where the characteristics being varied are the relative positions of the pulses, the frequency (repetition rate) of the pulses, the phase of the pulses, or the spacing (time) between the pulses.

SEE OR SEARCH CLASS:

375,	Pulse or Digital Communications, subclass 239 or 340+ for a combination of pulse position, frequency or spacing demodulator with receiving structure.

314	.. Including discrete semiconductor device:

This subclass is indented under subclass 313. Subject matter containing an electrical device whose constituent portions are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

315	FREQUENCY MODULATION DEMODULATOR:

This subclass is indented under the class definition. Subject matter where the demodulator extracts the modulating signal from a modulated signal which has undergone frequency modulation.

(1) Note. Frequency modulation occurs when the frequency of a carrier is varied over a continuum of values in accordance with the modulating signal.

(2) Note. This subclass includes frequency modulation demodulators, per se. See the SEARCH CLASS notes below for combinations with subject matter of this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

300+,	for a frequency shift keying or minimum shift keying demodulator.
311+,	for a pulse modulation demodulator.
345+,	for a phase modulation demodulator.
347+,	for an amplitude modulation demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 42+ for frequency demodulation in a system with separated transmitter and receiver, and subclasses 205+ for a combination of frequency demodulator with receiving structure.

316	. Plural demodulation:

	This subclass is indented under subclass 315. Subject matter which utilizes a diverse intermediate type of demodulator within the FM demodulator or combines the outputs of a plurality of FM demodulators or has an output selectable from a plurality of demodulators one of which must be an FM type.

317	.. Including amplitude demodulation:

	This subclass is indented under subclass 316. Subject matter which utilizes an intermediate amplitude demodulator.

318	. Having specific distortion, noise or other interference prevention, reduction or compensation:

This subclass is indented under subclass 315. Subject matter including the neutralization of an undesirable characteristic of a frequency modulation demodulator or its signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:

349+,

for distortion or noise control in an amplitude modulation demodulator.

SEE OR SEARCH CLASS:

455,

Telecommunications, subclasses 63.1 through 65and subclasses 501-506 for noise control in a telecommunication system with separated transmitter and receiver, subclasses 210-211 for carrier amplitude modulation elimination in an FM receiver and subclasses 296-312 for receiver noise or interference control, particularly subclasses 309 and 312.

319	.. Using feedback to reduce distortion, noise or other interference:

	This subclass is indented under subclass 318. Subject matter which utilizes a returned portion of the output signal to achieve neutralization.

320	.. By cancelling distortion, noise or other interference:

	This subclass is indented under subclass 318. Subject matter which combines a derived error or deviation signal with an intermediate demodulator signal to achieve neutralization of an undesirable characteristic in the final demodulator output.

321	.. Using amplitude limiting within the demodulator:

This subclass is indented under subclass 318. Subject matter which restricts the magnitude of signal fluctuations within the demodulator itself to achieve the neutralization.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 308+ and particularly subclass 309 for amplitude limiting in a receiver noise elimination structure.

322	. Including microwave or distributed parameter structure:

This subclass is indented under subclass 315. Subject matter utilizing a structure or device which is peculiar to microwave frequencies or which has resistance, inductance or capacitance not concentrated in lumped circuit elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:

354,	for similar structure in an amplitude modulation demodulator.

323	. Input signal combined with local oscillator or carrier frequency signal:

This subclass is indented under subclass 315. Subject matter where the modulated signal input to the demodulator interacts therein with oscillations from a secondary source.

(1) Note. The secondary oscillations may be internally generated or externally supplied and may be at a frequency other than that of the modulated input signal"s carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:

302,	for similar structure in a frequency shift keying or minimum shift keying demodulator.
306+,	for similar structure in a phase shift keying or quadrature amplitude demodulator.
346,	for similar structure in a phase modulation demodulator.
358+,	for similar structure in an amplitude modulation demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 208+ for synchronized or controlled local oscillator in a FM receiver and subclasses 255+ for generic local oscillator frequency control in a receiver.

324	.. Input signal applied directly to local oscillator:

	This subclass is indented under subclass 323. Subject matter in which the modulated input signal has a direct interaction with the secondary source of oscillations and where the modulating signal is extracted directly therefrom.

325	.. Including phase or frequency locked loop:

This subclass is indented under subclass 323. Subject matter in which a phase or frequency locked loop provides stability to the secondary source of oscillations.

SEE OR SEARCH CLASS:

331,	Oscillators, subclasses 1+ for phase or frequency locked loops, per se.
455,	Telecommunications, subclass 260 for phase lock loop or frequency synthesizer in a receiver.

326	... Including discrete semiconductor device:

This subclass is indented under subclass 325. Subject matter containing an electrical device whose constituent portions are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

327	. Input signal split into plural signals:

This subclass is indented under subclass 315. Subject matter where the modulated signal input to the demodulator is separated into a plurality of closely analogous or identical representations.

SEE OR SEARCH THIS CLASS, SUBCLASS:

363+,

for input signal splitting in an AM demodulator.

328	.. Including piezoelectric resonant element:

This subclass is indented under subclass 327. Subject matter which incorporates a resonant component having the ability to transform mechanical energy into electrical energy (e.g., piezoelectric).

(1) Note. Piezoelectric resonant elements are typically crystals.

SEE OR SEARCH CLASS:

310,	Electrical Generator or Motor Structure, subclasses 311+ for piezoelectric elements, per se.

329	.. Using a transformer to split input signal:

	This subclass is indented under subclass 327. Subject matter in which the separated signal representations are obtained at the various wound portions of a transformer (e.g., primary or secondary windings).

330	... Signals taken from primary and secondary windings:

	This subclass is indented under subclass 329. Subject matter where representations of the modulated input signal are extracted from the primary and the secondary windings of the transformer.

331	.... Including plural detector diodes (e.g., ratio detector type):

This subclass is indented under subclass 330. Subject matter which additionally utilizes a plurality of diodes in demodulation.

(1) Note. An example of this structure is a ratio detector where the ratio of a pair of diode rectified currents is proportional to frequency variations of an input signal.

332	... Signals taken from plural secondary windings:

	This subclass is indented under subclass 329. Subject matter where representations of the modulated input signal are extracted from plural secondary windings of the transformer.

333	.... Including plural detector diodes (e.g., ratio detector type):

This subclass is indented under subclass 332. Subject matter which additionally utilizes a plurality of diodes in demodulation.

(1) Note. An example of this structure is a ratio detector where the ratio of a pair of diode rectified currents is proportional to frequency variations of an input signal.

334	..... Including resonant circuits tuned above and below input signal carrier frequency:

	This subclass is indented under subclass 333. Subject matter which additionally utilizes a pair of tuned circuits having resonant frequencies above and below the carrier frequency of the input signal.

335	... Including plural detector diodes (e.g., ratio detector type):

This subclass is indented under subclass 329. Subject matter which additionally utilizes a plurality of diodes in demodulation.

(1) Note. An example of this structure is a ratio detector where the ratio of a pair of diode rectified currents is proportional to frequency variations of an input signal.

336	.. Input signal combined with phase shifted or delayed portion of input signal:

This subclass is indented under subclass 327. Subject matter in which an unmodified modulated signal is subsequently combined with a time delayed version thereof.

(1) Note. Such a time delay can also be considered to be a phase shift.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclass 304 for phase shifting among plural signal paths used in receiver noise elimination.

337	... Including lc resonant phase shift circuit:

	This subclass is indented under subclass 336. Subject matter in which an inductive-capacitive resonant network provides the required phase shift.

338	.. Input signal split by lc resonant circuit:

	This subclass is indented under subclass 327. Subject matter in which the input signal is separated into plural representations by an inductive-capacitive resonant circuit.

339	... Including lc resonant circuits tuned above and below input signal carrier frequency:

	This subclass is indented under subclass 338. Subject matter utilizing a pair of inductive-capacitive tuned circuits having resonant frequencies above and below the carrier frequency of the input signal.

340	.. Including plural detector diodes (e.g., ratio detector type):

This subclass is indented under subclass 327. Subject matter which additionally utilizes a plurality of diodes in demodulation.

(1) Note. An example of this structure is a ratio detector where the ratio of a pair of diode rectified currents is proportional to frequency variations of an input signal.

341	. Input signal converted to and processed in pulse form (e.g., pulse counter or digital type demodulator):

This subclass is indented under subclass 315. Subject matter in which the frequency modulated input signal is first changed to a pulse equivalent and then processed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

311+,

for pulse demodulators, per se.

342	.. Including discrete semiconductor device:

This subclass is indented under subclass 341. Subject matter containing an electrical device whose constituent portions are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

343	.. Including digital logic circuitry:

This subclass is indented under subclass 341. Subject matter which includes processing circuitry which is not exclusively of an analog nature.

(1) Note. Such components include, for example, AND gates, OR gates, and J-K flip-flops.

344	. Input signal passed through single demodulating path including resonant circuit:

	This subclass is indented under subclass 315. Subject matter in which the modulated input signal transits a single demodulating circuit path which contains a tuned circuit.

345	PHASE MODULATION DEMODULATOR:

This subclass is indented under the class definition. Subject matter where the demodulator extracts the modulating signal from a modulated signal which has undergone phase modulation.

(1) Note. Phase modulation occurs when the phase of a carrier is varied over a continuum of values in accordance with the modulating signal.

(2) Note. This subclass includes phase modulation demodulators, per se. See SEARCH CLASS notes below for combinations with the subject matter of this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

304+,	for a phase shift keying or quadrature amplitude demodulator.
311+,	for a pulse demodulator.
315+,	for a frequency demodulator.
347+,	for an amplitude demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 42+ for phase demodulation in a system with separated transmitter and receiver, and subclasses 205+ for a combination of phase demodulator with receiving structure.

346	. Input signal combined with local oscillator or carrier frequency signal:

This subclass is indented under subclass 345. Subject matter where the modulated signal input to the demodulator interacts therein with oscillations from a secondary source.

(1) Note. The secondary oscillations may be internally generated or externally supplied and may be at a frequency other than that of the modulated input signal"s carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:

302,	for similar structure in a frequency shift keying or minimum shift keying demodulator.
306+,	for similar structure in a phase shift keying or quadrature amplitude demodulator.
323+,	for similar structure in a frequency modulation demodulator.
358+,	for similar structure in an amplitude modulation demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 208+ for a synchronized or controlled local oscillator in a phase modulation receiver and subclasses 255+ for generic local oscillator frequency control in a receiver.

347	AMPLITUDE MODULATION DEMODULATOR:

This subclass is indented under the class definition. Subject matter where the demodulator extracts the modulating signal from an input AM signal.

(1) Note. Amplitude modulation is achieved by varying the amplitude of a carrier over a continuum of values in accordance with a modulating signal.

(2) Note. This subclass includes amplitude modulation demodulators, per se. See the SEARCH CLASS note below for combinations with the subject matter of this subclass.

SEE OR SEARCH THIS CLASS, SUBCLASS:

311+,	for a pulse demodulator.
315+,	for frequency modulation demodulator.
345+,	for a phase modulation demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 130+ for a telecommunication receiver utilizing an amplitude modulation demodulator as a subcombination thereof.

348	. Having plural demodulation outputs:

	This subclass is indented under subclass 347. Subject matter where there are more than one output signal which as undergone demodulation, one of which must have undergone amplitude demodulation.

349	. Having specific distortion, noise or other interference prevention, reduction or compensation:

This subclass is indented under subclass 347. Subject matter including the neutralization of an undesirable characteristic of an amplitude modulation demodulator or its signals.

SEE OR SEARCH THIS CLASS, SUBCLASS:

318+,

for distortion or noise control in a frequency modulation demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 63.1 through 65and 501-506 for noise control in a telecommunication system with separated transmitter and receiver, and subclasses 296-312 for receiver noise or interference control, particularly subclasses 309 and 312.

350	.. Automatic amplitude stabilization or control:

	This subclass is indented under subclass 349. Subject matter in which undesirable fluctuations in the magnitude of a demodulator signal are eliminated or reduced.

351	.. Nonlinearity reduction or compensation:

	This subclass is indented under subclass 349. Subject matter where an undesirable nonlinear characteristic of a demodulator, its components or its signals is neutralized.

352	.. Temperature compensation:

	This subclass is indented under subclass 349. Subject matter in which undesirable effects of ambient temperature on a demodulator are diminished.

353	.. Noise reduction or compensation:

This subclass is indented under subclass 349. Subject matter in which undesired signal components superimposed upon a desired demodulator signal are attenuated.

(1) Note. In some instances, noise is generated due to an inherent characteristic of a demodulator circuit component.

354	. Including microwave or distributed parameter structure:

This subclass is indented under subclass 347. Subject matter utilizing a structure or device which is peculiar to microwave frequencies or which has resistance, inductance or capacitance not concentrated in lumped circuit elements.

SEE OR SEARCH THIS CLASS, SUBCLASS:

322,	for similar structure in a frequency modulation demodulator.

355	.. With electron discharge device:

This subclass is indented under subclass 354. Subject matter utilizing a device which has electrical current flow between two spaced electrodes in a gas, vapor or vacuum.

(1) Note. This might include, for example, vacuum or gas tubes such as diodes, triodes or pentodes.

(2) Note. Additional control electrodes may be present.

356	. Suppressed carrier double sideband type:

This subclass is indented under subclass 347. Subject matter where the input AM signal has had the carrier attenuated and both sidebands are present.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclass 46 for a suppressed carrier system having separated transmitter and receiver and subclass 202 for a suppressed carrier- type receiver.

357	. Single or vestigial sideband type:

This subclass is indented under subclass 347. Subject matter where the input AM signal has less than two complete sidebands present.

(1) Note. The carrier may or may not be present in the input signal.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclass 47 for a single or vestigial sideband system with separated transmitter and receiver and subclasses 203 or 204 for a single sideband or vestigial sideband-type receiver, respectively.

358	. Input signal combined with local oscillator or carrier frequency signal (e.g., synchronous demodulator):

This subclass is indented under subclass 347. Subject matter where the modulated signal input to the demodulator interacts therein with oscillations from a secondary source.

(1) Note. The secondary oscillations may be internally generated or externally supplied and may be at a frequency other than that of the modulated input signal"s carrier.

(2) Note. A synchronous demodulator uses a local carrier frequency signal synchronized with the carrier of the modulated input signal to cancel out the modulated input signal"s carrier.

SEE OR SEARCH THIS CLASS, SUBCLASS:

302,	for similar structure in a frequency shift keying or minimum shift keying demodulator.
306+,	for similar structure in a phase shift keying or quadrature amplitude demodulator.
323+,	for similar structure in a frequency modulation demodulator.
346,	for similar structure in a phase modulation demodulator.

SEE OR SEARCH CLASS:

455,	Telecommunications, subclasses 255+ for generic local oscillator frequency control in a receiver.

359	.. Input signal applied directly to local oscillator:

	This subclass is indented under subclass 358. Subject matter where the input AM signal interacts directly with the local secondary source of oscillations.

360	.. Including phase or frequency locked loop:

This subclass is indented under subclass 358. Subject matter in which frequency stability is provided to the secondary source of oscillations by a phase or frequency locked loop.

SEE OR SEARCH CLASS:

331,	Oscillators, subclasses 1+ for phase or frequency locked loops, per se.
455,	Telecommunications, subclass 260 for phase locked loop or frequency synthesizer in a receiver.

361	.. Including sampling, gating or switching:

This subclass is indented under subclass 358. Subject matter which additionally includes signal processing of an interruptive or discrete nature.

(1) Note. This may include, for example, chopping of the modulated input signal.

362	... With three or more terminal discrete semiconductor device:

This subclass is indented under subclass 361. Subject matter utilizing an electrical device with three external connection points where the constituent portions of the device are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

363	. Input signal split into plural signals:

This subclass is indented under subclass 347. Subject matter in which the modulated signal input to the demodulator is separated into a plurality of closely analogous or identical representations.

SEE OR SEARCH THIS CLASS, SUBCLASS:

327+,

for input signal splitting in a frequency modulation demodulator.

364	.. Including three or more terminal discrete semiconductor device:

This subclass is indented under subclass 363. Subject matter utilizing an electrical device with three external connection points where the constituent portions of the device are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

365	.. Including diode demodulator device:

This subclass is indented under subclass 363. Subject matter utilizing a unidirectional electrical element as demodulator.

(1) Note. The diodes of this subclass may be either semiconductor or tube type.

366	... Plural diodes:

	This subclass is indented under subclass 365. Subject matter having a plurality of demodulating unidirectional electrical elements.

367	. Including regenerative feedback in nonoscillating demodulator:

	This subclass is indented under subclass 347. Subject matter in which an AM demodulator, not requiring a supplemental source of oscillations to achieve demodulation, positively feeds back a portion of its output to provide signal enhancement.

368	. Electron discharge demodulator device having more than two electrodes (e.g., triode, tetrode, etc.):

	This subclass is indented under subclass 347. Subject matter in which an AM demodulator utilizes a device which has electrical current flow between two spaced electrodes in a gas, vapor or vacuum and which current flow is controlled by an additional electrode.

369	. Including three or more terminal discrete semiconductor demodulator device:

This subclass is indented under subclass 347. Subject matter in which the AM demodulator utilizes an electrical device with three external connection points where the constituent portions of the device are constructed from solid material having room temperature conductivity between that of a conductor and an insulator and which conductivity is typically modified through the addition of small amounts of dopant.

(1) Note. This might include, for example, semiconductor diodes or transistors of diverse type.

370	. Including diode demodulator device:

This subclass is indented under subclass 347. Subject matter where the AM demodulator incorporates a unidirectional electrical element.

(1) Note. The diodes of this subclass may be either semiconductor or tube type.

371	. Coherer type demodulator:

This subclass is indented under subclass 347. Subject matter where the demodulating element includes conductors loosely resting against each other in imperfect conducting contact, the conductors being of such a material and shape that passage of a high frequency current therethrough modifies the conducting contact.

(1) Note. Usually the demodulating element is formed from loosely packed metallic granules, whose contact resistance decreases upon passage of a high frequency current therethrough. However, the contact resistance may increase under these conditions to constitute an anticoherer, which is also included here.

(2) Note. The coherer often includes structure, namely, a decoherer, for breaking the coherence established by the high frequency current.

SEE OR SEARCH CLASS:

178,	Telegraphy, subclass 117 for an alternating current teles:graphic system utilizing a coherer.
257,	Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), subclass 43 for active solid-state type coherers.
338,	Electrical Resistors, subclass 1 for coherer-type resistors, per se.