US PATENT SUBCLASS 375 / 272
.~.~ Frequency shift keying

Current as of: June, 1999
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375 /   HD   PULSE OR DIGITAL COMMUNICATIONS

259  DF  SYSTEMS USING ALTERNATING OR PULSATING CURRENT {4}
271  DF  .~ Angle modulation {2}
272.~.~ Frequency shift keying {6}
273  DF  .~.~.~> Combined with phase shift keying
274  DF  .~.~.~> Minimum shift keying
275  DF  .~.~.~> More than two frequencies
276  DF  .~.~.~> One cycle or less per bit
277  DF  .~.~.~> Vestigial or single sideband, or suppressed carrier
278  DF  .~.~.~> Antinoise or distortion

DEFINITION

Classification: 375/272

Frequency shift keying:

(under subclass 271) Subject matter where the instantaneous frequency of the pulse or digitally modulated carrier wave is shifted (generally between two frequencies) according to the presence or absence of a pulse, or a mark or space, being transmitted.

SEE OR SEARCH THIS CLASS, SUBCLASS:

211, for frequency shift keyed repeaters.

223, for frequency shift keyed transceivers.

303+, for frequency shift keyed transmitters.

334+, for frequency shift keyed receivers.

SEE OR SEARCH CLASS

359, Optics: Systems (Including Communication) and Elements, 182, for a frequency modulated light wave transmitter.