| 摘要 |
PROBLEM TO BE SOLVED: To provide an AGC amplifier circuit that can suppress dispersion in a minimum gain. SOLUTION: The AGC amplifier circuit consists of a parallel connection of a fixed gain amplifier 3 whose gain is not controlled by an AGC voltage and a variable gain amplifier 3 whose gain is controlled by the AGC voltage, and the gain of the AGC amplifier circuit is changed by the variable gain amplifier 3 when the AGC voltage is within a prescribed voltage range and constant by the fixed gain amplifier 2 when the AGC voltage is at the outside of the prescribed voltage range. The minimum gain of the AGC amplifier circuit is selected equally to the gain of the fixed gain amplifier.
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