US PATENT SUBCLASS 375 / 309
.~ Keying circuits

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

295  DF  TRANSMITTERS {6}
309.~ Keying circuits {6}
310  DF  .~.~> Remote controlled
311  DF  .~.~> Automatic
312  DF  .~.~> Power or bias voltage supply keying
313  DF  .~.~> Key shock or click prevention
314  DF  .~.~> Including auxiliary control tube
315  DF  .~.~> Modulation by absorption of signal, changing antenna dimension or changing antenna impedance

DEFINITION

Classification: 375/309

Keying circuits:

(under subclass 295) Subject matter wherein the output signal of the transmitter is initiated and terminated by a keying device, such as a manually or automatically operated switch.

(1) Note. The keying device may control the active elements of the transmitter (oscillator or modulator) or the coupling circuits.

(2) Note. Where the claims are drawn to a keying device controlling an oscillator or an amplifier without additional details of the transmitter, classification is in Class 331, subclasses 172+ or Class 330, respectively.

SEE OR SEARCH CLASS

178, Telegraphy,

116, for keyed spark gap or arc converter transmitters.

359, Optics: Systems (Including Communication) and Elements,

182, and 183 for an angle modulated light wave transmitter.