Manual adjustment circuit for pilot tone regulators - uses differential amplifier switched between servo and level detector

摘要

The system for the manual adjustment of pilot tone controlled level regulator circuits consists of a high gain differential amplifier (DV) with one input (Ei) connected to the output of the setter (ST), and the second input connected to the slider of a reference voltage potentiometer (PT). The amplifier output can be connected via a change-over switch (S1) to the input of the level detector (PD). In this position of teh switch, a second contact (S2) connects the potentiometer slider and one input of the differential amplifier to the input of the servo-amplifier stage (VS). By rotating the calibrating potentiometer, the input voltage at the servo-amplifier is adjusted as required to the set point, and the pilot tone regulator is so set that the output voltage of the setter varies between two values of input voltage at the servo-amplifier. Both these voltages are practically identical.