MODULATOR.

摘要

The modulator recorder has a difference amplifier (6) comparing the input signal with a reference signal providing a pair of output signals each fed to one input of two further difference amplifiers (9,22). The second inputs of these amplifiers are each supplied with a carrier signal and their outputs provide the modulated signal. The difference between the outputs of the first difference amplifier (6) is fed to a lowpass filter (25) providing a signal for a regulating amplifier (40) providing the reference signal for the first difference amplifier.