(under the class definition) Subject matter including a periodic switching means common to the input and output circuits of the amplifier.
(1) Note. This subclass includes essentially four types of subject matter containing a periodic switch, as follows:
(a)
Where the signal is chopped to get A.C. which is fed to the amplifier and the amplifier output is chopped to get a D.C.. output (this subject matter is the same as is classified in subclass 10 below except that the modulator and demodulator are of the chopper type).
(b)
The signal to the main amplifier is not chopped but a portion to another amplifier is combined with a signal from the output of the first amplifier and the two are chopped to get an A.C. signal which is used to develop a corrective signal for the main amplifier.
(c) The input is compared to the output by a periodic switch to develop a correction signal, generally for drift correction.
(d)
The input and output signal are combined and then chopped and put into the main amplifier.
SEE OR SEARCH THIS CLASS, SUBCLASS:
83, for push-pull signal feedback amplifiers having a D.C.. feedback path.
97, for signal feedback amplifiers having a D.C.. feedback path.
121, for push-pull amplifiers having D.C.. interstage coupling.
125, for plural amplifiers having a D.C.. and an A.C. channel.
159, 161, 163, and 181+, for D.C.. coupling involved in the interstage coupling.
