| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplitude control circuit which increases the number of channels of an input sound signal and gains a high-quality output sound signal regarding all the channels. SOLUTION: In AGC circuits 100a and 100b which have the same constitutions, connection terminals 106a and 106b are connected to each other, both connection terminals 107a and 107b are connected to one end of a capacitor C1, one switching circuit 105a only is closed, and the other is open. At this time, a signal having a higher voltage out of each output signal of both wave rectifying circuits 102a and 102b is inputted in a comparator 104a, a current source I1a or I2a is operated according to the comparison result of the voltage of the signal with a reference voltage Vref, and the capacitor C1 is charged and discharged. Every adjusting amplifier 101a and 101b adjusts amplitudes of the output signals SOUT_1 and SOUT_2 according to the charged voltage of the capacitor C1. COPYRIGHT: (C)2006,JPO&NCIPI
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