US PATENT CLASS 329
Class Notes
Current as of: June, 1999
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DEFINITION
Classification: 329/
A. BASIC SUBJECT MATTER OF CLASS
This is the generic class for demodulators. A demodulator is a device which extracts an arbitrarily varying information carrying signal from a signal formed by varying a characteristic of a repetitious electrical or electromagnetic wave of less than infrared frequency in accordance with this information carrying signal. Classification herein is broadly by the type of modulation exhibited by the input signal.
B. COMBINATIONS WITH BASIC SUBJECT MATTER INCLUDED IN THIS CLASS
1. A demodulator combined with perfecting structure is classified here. Such structure might include, for example, a particular power supply for electronic devices within the demodulator.
2. A demodulator combined with or incorporated in other structure not otherwise classifiable is classified here. This might include, for example, a demodulator combined with an acoustical device such as a loudspeaker.
3. A combination including both a modulator and a demodulator is classified elsewhere. See Lines With Other Classes and Within This Class, below.
C. MISCELLANEOUS SYSTEMS AND DEVICES USED WITH DEMODULATORS
This class provides for (1) miscellaneous systems and devices which are not of general utility and which are limited to use with demodulators and (2) miscellaneous systems and devices useful with demodulators which are not otherwise classified. An example of this would be convertible demodulators which convert between different types of demodulators or which convert to or from devices other than demodulators. LINES WITH OTHER CLASSES
A combination including both a modulator and a demodulator is classified in Class 332 where such combination is not provided for elsewhere.
Excluded from this class are pulse code demodulators and delta modulation demodulators which are now classified elsewhere. See References to other Classes, below.
Several classes contain structure which is closely analogous to demodulators. Particularly significant among these is the art in the class for miscellaneous active electrical nonlinear devices, circuits, and systems. See the relevant SEARCH CLASS notes below in References to Other Classes in completing the search for subject matter of Class 329.
Many classes contain subject matter which includes demodulators or analogous devices as subcombinations thereof. Among these are receivers and complete communication systems (i.e., transmitters and receivers). (See References to Other Classes, below.) Therefore, these classes and others contained in the SEARCH CLASS notes below in References to Other Classes, should be considered in completing the search for subject matter of Class 329.
The terms "discriminator" and "detector" are often but not always used synonymously with "demodulator". Classification in Class 329 is appropriate where the terms "discriminator" or "detector" are recited and which clearly disclose a corresponding function of demodulation per the definition above. Classification is elsewhere where no such disclosure is present. See the SEARCH CLASS notes below in References to Other Classes, particularly those for the class for miscellaneous active electrical nonlinear devices, circuits, and systems.
Demodulators having a modulated input of less than infrared frequency which may utilize an internal optical element (e.g., an optical isolator) are classified in Class 329 by the type of modulation.
The combination of modulation converter (e.g., FM to AM) with a demodulator is classified in Class 329 according to the modulation type of the input to the converter. Modulation converters, per se, are classified elsewhere. See References to Other Classes, below.
For classification herein there must be complete extraction of the modulating signal. Mere frequency converters (e.g., RF to IF mixers) are not classified here. See References to Other Classes, below.
Class 329 provides for demodulators, per se, with structure for noise or distortion control (see Subclass References to the Current Class, below). Class 455, Telecommunications, provides for noise or interference control in: (a) a telecommunication system (i.e., transmitter and receiver); (b) a complete telecommunication receiver; and (c) a combination of two or more receiver elements (viz. wave collector, wave mixer or modifier, demodulator, and utilization device) where the combination is not elsewhere classified. Therefore, consideration must be given to extending the search for demodulator noise control circuitry into relevant subclasses of Class 455. See also the SEARCH CLASS notes in References to Other Classes, below, relating to Class 455.
Subclasses of this class (329) relate to suppressed carrier double sideband demodulators, per se, and single/vestigial sideband demodulators, per se (see Subclass References to the Current Class, below). Class 455 accepts this subject matter in combination with what may be broadly recited diverse receiver elements (viz. wave collector, wave modifier or mixer, and utilization device). Therefore, in completing the search for demodulators of an amplitude modulated wave not having the full complement of carrier and two complete sidebands, consideration must be given to extending the search to relevant subclasses in Class 455. See also the SEARCH CLASS notes in References to Other Classes, below, relating to Class 455. SEE OR SEARCH THIS CLASS, SUBCLASS:
318+, and 349+ for demodulators, per se, with structure for noise or distortion control.
356, for suppressed carrier double sideband demodulators, per se.
357, single/vestigial sideband demodulators, per se.
REFERENCES TO OTHER CLASSES
SEE OR SEARCH CLASS
73, Measuring and Testing, appropriate subclasses for measuring or testing of a parameter which is typically neither electrical, optical, thermal, nor chemical and which
may include a demodulation technique.
178, Telegraphy,
66.1+, for a teles:graphic system which transmits messages between stations using alternating or pulsating currents and particularly subclass 66.2 for such a system having a transmitter which is turned on and off, subclass 117 for a teles:graphic system utilizing a coherer, and subclasses 118+ for teles:graphic receivers in general.
250, Radiant Energy, appropriate subclasses for the detection of invisible radiation or the testing of material by invisible radiation which may include a modulation - demodulation technique.
257, Active Solid-State Devices (e.g., Transistors, Solid-State Diodes), appropriate subclasses for active solid-state devices used as demodulators, including 10, 11, 21, 53-56, 113-118, 184-189, 225-234, 257-258, 290-294, and 414-466 for radiation-sensitive active semiconductor devices.
307, Electrical Transmission or Interconnection Systems,
401+, for miscellaneous nonlinear reactor systems.
310, Electrical Generator or Motor Structure,
311+, for piezoelectric elements and devices.
313, Electric Lamp and Discharge Devices, appropriate subclasses for the structure of electronic tubes.
315, Electrical Lamp and Discharge Devices: Systems,
1+, for cathode-ray tube circuits with power supply or the combination of cathode-ray tube and circuit element in a unitary device, and subclasses 94+ for an electron discharge device which is an ultimate load together with a cathode or cathode heater supply circuit.
318, Electricity: Motive Power Systems,
606+, for servo systems utilizing a feedback signal which frequency or phase modulates a system carrier (particularly subclasses 607 and 608 for obtaining the modulating wave by reference signal frequency or phase comparison, respectively) subclass 622 for an AC lead or lag network which may include a demodulation technique, and subclasses 671+ for particular servo system motor control (particularly subclass 684 which utilizes a specific demodulator).
323, Electricity: Power Supply or Regulation Systems, appropriate subclasses for control of the magnitude or phase of current or voltage in a system comprising a single
electrical source coupled to a single electrical load. 324, Electricity: Measuring and Testing, appropriate subclasses for measurement of electrical properties, in general, and particularly
76.11+, for systems measuring and testing electricity which may include demodulation, particularly subclasses 76.39+ for frequency measurement and subclasses 76.77+ for phase comparison, and subclass 118 for modulation of voltage or current to be measured onto a carrier combined with subsequent structure to recover a replica of the original voltage or current by demodulation.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,
1+, for miscellaneous signal parameter discriminating or comparing for input signals not carrying intelligence, particularly subclasses 2+ for miscellaneous phase discriminating, subclasses 31+ for miscellaneous pulse spacing discriminating, subclasses 39+ for miscellaneous frequency discriminating, and subclasses 50+ for miscellaneous amplitude discriminating. (See Lines With Other Classes, above)
330, Amplifiers,
10, for an amplifier having an input which is the output of a modulator and an output which is the input of a subsequent demodulator.
331, Oscillators,
1+, for automatic oscillator frequency stabilization using phase or frequency sensing which may include comparison with a reference oscillator or a modulation technique, subclasses 46+ for plural oscillator systems in general, and subclass 58 for an oscillator with structure to perform an additional simultaneous function.
332, Modulators,
100+, for a frequency shift keying modulator, subclasses 103+ for a phase shift keying modulator, subclasses 106+ for a pulse modulator, subclasses 117+ for a frequency modulator, subclasses 144+ for a phase modulator and subclasses 149+ for an amplitude modulator; subclasses 183+ for modulation converters, per se.
333, Wave Transmission Lines and Networks,
24+, for transmission line coupling networks (particularly subclasses 25+ for balanced to unbalanced circuits, subclasses 138+ for lumped parameter delay lines, and subclasses165 - 212 for filters), subclasses 236+ for long lines, per se, and subclasses 245+ for long line elements and components.
334, Tuners, appropriate subclasses for tuner circuits, per se, which may include a broad recitation of a demodulator plus details of a tuner and particularly
30+, for a tuner with a resonance indicator in which a demodulator may be used and subclass 39 for tuners combined with other devices which may include a demodulator recited broadly.
336, Inductor Devices, appropriate subclasses for electrical circuit elements exhibiting inductive properties.
338, Electrical Resistors,
1, for a coherer-type resistor and subclasses 13+ for a resistor whose resistance value varies in response to a condition such as temperature or magnetic field.
340, Communications: Electrical,
870.01+, for telemetry systems and especially subclasses 870.18+ indented thereunder for such systems where the quantity to be telemetered is imposed on a carrier by a particular type of modulation.
341, Coded Data Generation or Conversion,
126+, for a pulse code demodulator, per se, and subclass 143 for a delta modulation demodulator, per se.
342, Communications: Directive Radio Wave Systems and Devices (e.g., Radar, Radio Navigation),
350+, for directive radio wave systems which may include demodulation techniques and particularly subclasses 385+ for a directive beacon or receiver. 348, Television,
638+, for a demodulator particularly adapted for extracting a component of a natural color television signal from a carrier or subcarrier, subclasses 726+ for television signal receivers and subcombination thereof.
358, Facsimile,
469, for modulation onto a carrier of a facsimile signal derived from scanning a picture or for demodulation of such a modulated carrier to reconstruct the picture.
360, Dynamic Magnetic Information Storage or Retrieval,
28, for control of a demodulator by a reference carrier signal stored concurrently with the information signal to be demodulated and subclasses 29+ for dynamic magnetic recording
or reproducing containing particular demodulator circuitry.
363, Electric Power Conversion Systems, particularly
13+, for current conversion which includes generic AC to DC rectifiers and generic DC to AC inverters of diverse type.
367, Communications, Electrical: Acoustic Wave Systems and Devices,
134, for acoustic wave demodulation in an underwater telemetry system.
369, Dynamic Information Storage or Retrieval, 90, for demodulation of a previously modulated quadraphonic subchannel signal after retrieval.
370, Multiplex Communications, appropriate subclasses for multiplexing systems which may utilize demodulation techniques.
374, Thermal Measuring and Testing, appropriate subclasses for measurement systems responsive to an external thermal condition which may utilize a modulation technique.
375, Pulse or Digital Communications, appropriate subclasses for demodulators combined with receiving structure to couple a modulated pulse wave from a transmission medium (i.e., a receiver) or complete systems (i.e., transmitter and receiver) incorporating such a combination, particularly
237, 242 + for a system or receiver utilizing pulse number modulation, pulse width modulation, pulse position, frequency, or spacing modulation, pulse amplitude modulation, or pulse code modulation, subclasses 259+ for other diverse types of digital communication systems which may include a particular demodulator, and subclasses 316+ for other diverse types of digital communication receivers which may include a particular demodulator. (also see Lines With Other Classes, above)
380, Cryptography, for all electrical communications equipment which process an information signal for purposes of concealment.
381, Electrical Audio Signal Processing Systems and Devices,
1+, for broadcast stereophonic signal processing not elsewhere classified.
386, Television Signal Processing for Dynamic Recording or Reproducing,
26+, for frequency modulation of a color television signal.
455, Telecommunications, appropriate subclasses for
nondigital demodulators combined with receiving structure to couple a modulated wave from a transmission medium (i.e., a receiver) or complete systems (i.e., transmitter and receiver) incorporating such a combination, particularly 21, for frequency conversion in a repeater including a demodulator, subclasses 39+ for separated transmitter and receiver which may include a particular demodulator, subclasses 73+ for a transceiver which may include a particular demodulator, and subclasses 130+ for a telecommunications receiver which may include a particular demodulator; subclasses 202 and 204 for suppressed carrier double sideband demodulators, per se, and single/vestigial sideband demodulators, in combination with what may be broadly recited diverse receiver elements (viz. wave collector, wave modifier or mixer, and utilization device); subclasses 313+ for mere frequency converters (e.g., RF to IF mixers). (also see Lines With Other Classes, above)
GLOSSARY:
ARBITRARILY VARYING
Indicates having a future value which is not predictable from past values. (Arbitrary is the opposite of repetitious).
CARRIER
An electrical or electromagnetic repetitious sinusoidal wave.
CHARACTERISTIC
An attribute associated with the size or shape of a wave or signal. Examples are amplitude, frequency, or phase of a sine wave and repetition rate, position, amplitude, or width of a nonsine wave.
DEMODULATOR
A device which extracts an arbitrarily varying modulating signal from an electrical or electromagnetic modulated signal of less than infrared frequency.
MODULATED SIGNAL
A repetitious wave which has had a characteristic thereof varied by a modulating signal. MODULATING SIGNAL
An information carrying signal whose informational content is to be impressed on a carrier or pulse wave.
MODULATOR
A device which varies a characteristic of a repetitious
electrical or electromagnetic wave of less than infrared frequency in accordance with a characteristic of an arbitrarily varying modulating signal.
PULSE WAVE
An electrical or electromagnetic repetitious nonsinusoidal wave. Examples are square wave, saw-tooth wave, or trapezoidal wave.
REPETITIOUS WAVE
A cyclic wave whose individual component cycles are substantially identical. Examples of repetitious waves are sine waves, square waves, saw-tooth waves and trapezoidal waves.