.~ With control of input electrode or gain control electrode bias {13}
130
.~.~ Bias controlled by separate external control source
DEFINITION
Classification: 330/130
(under subclass 129) Subject matter wherein the "means to control the bias voltage" includes a source of control voltage from a system outside the amplifier system itself.
(1) Note. An example is a seismic amplifier wherein a battery not involved in supplying amplifier power or bias voltage charges an RC circuit which is applied to the control grid or an input grid of the amplifier when the shot blast is fired. Such additional means where it includes the detector or other related means of the seismic system, per se, is not classified herein. See the Search Class notes below..
(2) Note. Subject matter, wherein the control voltage is derived from a special pilot frequency voltage transmitted to the amplifier with the signal to be amplified, is not classified herein.
(3) Note. Subject matter wherein an oscillator (exclusive of any other source external to the amplifier) supplies the control bias is not classified herein. Also sources of bias voltage as such, where no cooperation from a system outside the amplifier is involved are classified with amplifiers. Where specific details of the external system are claimed as in the example under (1) Note above, as qualified in the last three lines, classification is not with amplifiers but with the external system.
SEE OR SEARCH THIS CLASS, SUBCLASS:
51, for amplifiers combined with automatic disabling switch means.
52, for subject matter, wherein the control voltage is derived from a special pilot frequency voltage transmitted to the amplifier with the signal to be amplified. See (2) Note above.
85, for amplifiers having an amplifier in the feedback path including bias control means for an electrode of such amplifier.
86, for amplifiers having a variable impedance in a feedback control path varied by a separate control path.
137, for amplifiers having bias control means including an oscillator in the control means. See (3) Note above.
143, for amplifiers having a thermally responsive impedance which may be controlled from an external control source.
144+, for amplifiers having a variable impedance for the signal channel controlled by a separate control path which may be from an external source.
SEE OR SEARCH CLASS
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,
309+, for miscellaneous circuits including bias voltage control means for amplitude limiting.
333, Wave Transmission Lines and Networks,
15, 16 and 17.1+ for pilot line, pilot current and automatically controlled passive wave transmission systems.
367, Communications, Electrical: Acoustic Wave Systems and Devices 14+, for means means where including the detector or other related means of the seismic system, per se. See (1) Note above.
455, Telecommunications, particularly
232.1+, and 341+, for similar subject matter in radio receivers.
