Patent ID: 6069533
Filing Date: 2000-05-30
Classification: H03F

Abstract:
A circuit for automatically adjusting a common mode rejection ratio of a balance circuit to improve tone quality in an acoustic apparatus if an audio/video system, comprising:first and second channel input terminals for respectively receiving first and second channel input signals;a mixing circuit for mixing said first and second channel input signals received through said first and second channel input terminals, eliminating noise from said first and second channel input signals, and providing a corresponding mixing circuit output signal through an output terminal; anda controller for simultaneously providing a direct current (DC) voltage having a predetermined level to said first and second channel input terminals when a main power source is initially applied, detecting a voltage level of said mixing circuit output signal, and controlling the voltage level of said mixing circuit output signal based on the detected voltage level by automatically adjusting a common mode input resistance of said mixing circuit according to the detected voltage level of said mixing circuit output signal.