(under the class definition) Amplifier systems wherein there are at least two signal channels each containing an amplifier as defined in the class definition, (Section I).
(1) Note. For this and indented subclasses such amplifier channels may be separate; in parallel with a common source and a common load; or in branched circuit channels from separate sources or to separate loads.
(2) Note. Sum and difference amplifiers involving two or more signal inputs to the same channel or a different channel where the output is proportionally the sum or difference of the plural inputs are not classified herein. See the search notes below.
(3) Note. A balanced circuit is regarded as a single source or load for the purposes of classification in these subclasses. A push-pull amplifier is regarded as a single amplifier channel for purposes of classification in this class. Balanced circuits and push-pull amplifiers are to be
found in this class.
(4) Note. The plural channels need not amplify or operate simultaneously to be classified herein. Subject matter involving plural channels with switching means to select with alternatively one or more channels to amplify a signal a classified in this or indented subclasses.
SEE OR SEARCH THIS CLASS, SUBCLASS: 3, for amplifiers having diverse type amplifying devices.
53, for amplifiers having distributed parameter coupling.
55, for amplifiers having distributed parameter coupling;
69, for sum and difference amplifiers. See (2) Note above.
70+, for amplifiers with series arranged amplifier devices.
71+, for series energized amplifier devices;
73, for plural outputs.
74, for plural separate signal inputs.
77, for push-pull amplifiers with feedback compensation for the effects of inter-electrode capacitance (e.g., neutralization);
81+, for signal feedback amplifiers having at least one push-pull stage;
84, for signal feedback amplifiers with plural amplifier channels.
116, for amplifiers with balanced-to-unbalanced coupling; 117+, for amplifiers having unbalanced-to-balanced coupling; and subclasses
118+, for amplifiers including a push-pull stage.
147, for amplifiers having plural input sources.
148, for amplifiers having plural loads.
151, for cascaded amplifiers with means to by-pass a stage.
252+, and 295, for plural semiconductor amplifier channels.
262+, 301 for semiconductor amplifiers;
SEE OR SEARCH CLASS
307, Electrical Transmission or Interconnection Systems,
11+, and 43+ for plural load circuit and supply circuit systems respectively.
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems, appropriate subclasses for miscellaneous nonlinear circuits utilizing electron tube or semiconductor devices. 333, Wave Transmission Lines and Networks,
1+, for plural channel passive network systems.
381, Electrical Audio Signal Processing and Systems,
77, for program distribution systems involving distribution of a program to a plurality of local stations where the program is amplified and reproduced.
