| 摘要 |
PROBLEM TO BE SOLVED: To provide an AGC circuit for eliminating the need for an integration circuit comprising resistors and capacitors. SOLUTION: When a variable gain control circuit 1 controlled by a gain control voltage V8 amplifies or attenuates an input signal, a rectifier circuit 2 rectifies an output signal of the variable gain control circuit 1, and a voltage comparator 3 compares an output signal of the rectifier circuit 2 with an optionally set voltage. An output signal of the voltage comparator 3 applies switching control between an up-count operation and a down-count operation of an up/down counter 5 and a D/A conversion circuit 5 outputs a voltage in response to the count of the up/down counter 5. Then the D/A conversion circuit 5 supplies the gain control voltage V8 corresponding to its output voltage to the variable gain control circuit 1. COPYRIGHT: (C)2004,JPO&NCIPI
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