COMPRESSING APPARATUS PROVIDED WITH AUTO LEVEL ADJUSTMENT FUNCTION, ESPECIALLY PREVENTING DISTORTION OF SIGNAL

摘要

PURPOSE: A compressing apparatus provided with an auto level adjustment function is provided to prevent the distortion of signal by adjusting the input current of the input terminal amplifier when the voice signal is applied as an over-input. CONSTITUTION: A compressing apparatus provided with an auto level adjustment function includes an input terminal amplifier(30), an add amplifier(32), a buffer amplifier(34), a rectifier(36), an auto level adjustment(38), a first gain cell(40) and a second gain cell(42). The input amplifier amplifies the value obtained by subtracting the input current from the first gain current. The add amplifier amplifies the sum of the output of the input terminal amplifier and the second gain current. A buffer amplifier outputs the temporally delayed output from the add amplifier as the output of the compressing apparatus. The rectifier converts the output of the add amplifier from alternative current to the direct current. The auto level adjustment compares the output of the rectifier with the reference voltage and generates the control signal when the output of the rectifier is larger than the reference voltage. The first gain cell generates the first gain current corresponding to the output of the buffer amplifier and the output of the rectifier. And, the second gain cell generates the second gain current corresponding to the output of the add amplifier and the output of the rectifier.