US PATENT SUBCLASS 330 / 278
.~ Including gain control means

Current as of: June, 1999
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330 /   HD   AMPLIFIERS

250  DF  WITH SEMICONDUCTOR AMPLIFYING DEVICE (E.G., TRANSISTOR) {21}
278.~ Including gain control means {4}
279  DF  .~.~> And significant control voltage developing means {2}
282  DF  .~.~> Having feedback means acting as variable impedance {1}
284  DF  .~.~> Having attenuation means in signal transmission path
285  DF  .~.~> Having particular biasing means

DEFINITION

Classification: 330/278

Including gain control means:

(under subclass 250) Subject matter including circuitry which controls the amplification of the applied signal.

SEE OR SEARCH THIS CLASS, SUBCLASS:

52, for amplifiers having pilot frequency control means.

96, for feedback amplifiers combined with control of bias voltage of a signal amplifier.

123, for push-pull amplifiers having significant power or bias supply circuits including those with bias control means.

127+, for amplifiers with control of power supply or bias voltage.

143, for amplifiers having a thermally responsive impedance.

144+, for amplifiers having a variable impedance in the signal path varied by a separate control path. 155+, for amplifiers having unicontrol of coupling or

associated circuits including unicontrol of signal input or output potentiometers, etc..

157+, 185+ and 192+, for interstage input or output coupling, respectively, including variable impedance means in such coupling.

254, for gain control means in combination with a differential amplifier.

SEE OR SEARCH CLASS

333, Wave Transmission Lines and Networks, particularly

14, 16, and 17.1 for combined amplifier compressor and expander means, pilot controlled means, and automatically controlled systems, respectively; subclasses 24+ for coupling networks which may include signal amplitude control means; subclasses 213+ for negative resistance and/or reactance networks of the active element type; and subclass 81 for attenuators.

455, Telecommunications,

232.1+, for volume control, especially subclasses 234.1+ for automatic volume control.