(under subclass 7) Subject matter including apparatus to change the frequency of the modulated carrier wave.
(1) Note. For classification in this subclass it is not necessary that the carrier frequency of the transmitted signal be different from the carrier frequency of the received signal. For example, the frequency of the received carrier wave may be converted to a lower frequency for purposes of amplification and then be reconverted to the original frequency for transmission.
SEE OR SEARCH CLASS
327, Miscellaneous Active Electrical Nonlinear Devices, Circuits, and Systems,
113+, for miscellaneous frequency control or conversion.
331, Oscillators,
37+, for means to produce a beat frequency by combining the output of two or more oscillators.
332, Modulators, appropriate subclasses for frequency conversion modulation systems, per se.
