(under subclass 76) Subject matter having means to modulate the voltage or current being measured onto a carrier wave and having further means to demodulate the resulting modulating carrier wave into a replica of the original voltage or current.
(1) Note. This subclass relates, for example, to direct current voltmeters which measure a very small direct current voltage which small voltage is amplified in the modulator-demodulator apparatus so that it is large enough to actuate a conventional meter.
SEE OR SEARCH CLASS
329, Demodulators, appropriate subclasses for demodulators, per se.
330, Amplifiers,
10, for modulator-demodulator amplifiers, per se.
332, Modulators, appropriate subclasses, for modulators.
