Signal processor

摘要

An operational amplifier (1) and resistors (11) and (12) damp an input signal (V1) by -6dB. Since a positive input terminal of the operational amplifier (1) is fixed at -3V, DC component of the input signal (V1) is down-shifted to -3V so that a signal (V2) is obtained. The signal (V2) is inputted to an electronic volume (100) wherein the signal (V2) is damped thereby a signal (V3) is obtained. An operational amplifier (2) and resistors (13) and (14) amplify the signal (V3) by 6dB. Since a positive input terminal of the operational amplifier (2) is fixed at OV, DC component of the signal (V3) is up-shifted to OV thereby a signal (V5) is obtained. The signal which is to be processed in the electronic volume has only a half voltage relative to that of the input signal.