US PATENT SUBCLASS 455 / 296
.~ Noise or interference elimination

Current as of: June, 1999
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455 /   HD   TELECOMMUNICATIONS

130  DF  RECEIVER OR ANALOG MODULATED SIGNAL FREQUENCY CONVERTER {24}
296.~ Noise or interference elimination {10}
297  DF  .~.~> In vehicle
298  DF  .~.~> Originating in power supply {1}
300  DF  .~.~> By shielding {1}
302  DF  .~.~> Image frequency suppression
303  DF  .~.~> Using plural separate signal paths {2}
307  DF  .~.~> With specific filter structure
308  DF  .~.~> With amplitude limiter {1}
310  DF  .~.~> Internally generated noise or oscillations
311  DF  .~.~> In radio frequency amplifier, intermediate frequency amplifier or converter circuit
312  DF  .~.~> In demodulator or low frequency (e.g., audio frequency)

DEFINITION

Classification: 455/296

Noise or interference elimination:

(under subclass 130) Subject matter having structure to (a) suppress the influence of extraneous electric or magnetic fields upon receiver circuitry, (b) prevent radiation of undesired electric or magnetic fields from the receiver circuitry, or (c) prevent translation through, or suppress at some point in, the receiver system any undesired modulation components accompanying a desired modulation carrier wave input signal which components are due to electrical disturbances within the useful frequency band or any undesired carrier wave, which may originate at a source external to the receiver wave input or collection means and arrive at the input or collector simultaneously with the desired modulated carrier wave.

(1) Note. The extraneous fields or undesired components may be due to external sources or internally generated noises or disturbances due to microphonica or regenerative effects.

SEE OR SEARCH THIS CLASS, SUBCLASS:

63+, for complete systems with noise prevention.

175.1+, for frequency selection (tuning) means combined with muting means.

219, for volume control systems combined with noise squelch means.

278.1+, for plural antennas with noise elimination means connected to a receiver. 283+, for subject matter relating to noise or static reduction or eliminating means within the coupling circuit between a collector (antenna) means and the input terminals of a receiver.

295+, for receivers with signal intermodulation or cross talk correction or elimination means.

298+, for receivers with hum or interaction prevention means in the power or bias supply.

317+, for frequency modifying or conversion systems including means for the prevention of unwanted oscillations.

501+, for complete systems comprising a plurality of transmitters or receivers with noise reduction.

SEE OR SEARCH CLASS

327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,

310+, for transient reduction by limiting or clipping, subclasses 379+ for miscellaneous reduction of gating noise, and subclasses 551+ for miscellaneous unwanted signal suppression.

330, Amplifiers, appropriate subclasses for amplifiers with limiting means.

340, Communications: Electrical,

600, for systems for detecting a signal bearing useful information accompanied by noise.

343, Communications: Radio Wave Antennas, 5+, for object detection radar systems having noise or interference prevention means; and subclasses 100+ for directive radio wave receivers which may have interference prevention means.

348, Television,

607+, for noise elimination in television systems.

370, Multiplex Communications, appropriate subclasses for multiplex systems having interference suppression.

375, Pulse or Digital Communications,

285, for complete systems utilizing pulse modulation and having distortion or noise prevention means; and subclasses 346+ for pulse type receivers with interference or noise

reduction means.