Circuit arrangement for deriving a level control signal using silicon diodes

摘要

A circuit arrangement for deriving a control signal from an audio input signal for level-controlled audio systems comprises a first amplifier/comparator and a first silicon diode for coupling its output signal to a first circuit junction. A feedback circuit is provided for coupling the signal at the first circuit junction to the input of the first amplifier/comparator. A second amplifier/comparator is provided having its output coupled to a second silicon diode which passes its output signal to a second circuit junction. A first feedback resistor is provided to apply the signal at the second circuit junction to the input of the second amplifier/comparator and a second feedback resistor applies an output signal from the second amplifier/comparator to the input thereof. The arrangement is such that the audio input signal is applied to at least one of the first and second amplifier/comparators and one of the first and second circuit junctions is connected to a time constant circuit so that the signal applied thereto comprise linearly detected, unipolar halfwaves of the input signal. The first and second feedback resistors are chosen so that desired operating characteristics are obtained.