| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic gain control circuit capable of dissolving fluctuation of a gain due to temperature characteristics of forward voltage drop. SOLUTION: An automatic gain adjustment circuit 1 adjusts the gain of an electric signal from an input terminal 2 to an output terminal 3, has: an operational amplifier OP1 which performs output according to difference between a control signal and a feedback signal; a transistor TR1 which supplies a power source according to the output of the operational amplifier OP1 from the input terminal 2 to the output terminal 3; a diode D3 arranged on a line 5 from the input terminal 2 to the output terminal 3, and diodes D1, D2 for temperature compensation which compensates change of the temperature characteristics of the forward voltage drop of at least of the transistor TR1 and the diode D3 are arranged on a line for inputting the feedback signal to the operation amplifier OP1. COPYRIGHT: (C)2010,JPO&INPIT
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