| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable gain amplifier capable of achieving both extension of a gain variable range and reduction of nonlinear distortion. SOLUTION: The variable gain amplifier includes an operational amplifier 1, a variable resistance circuit 2, and a control circuit 3. The variable resistance circuit 2 is composed of a plurality of variable resistance elements 21 and 22 connected in series. Each of the variable resistance elements has a resistance value according to a given control voltage. In addition, the variable resistance circuit 2 is connected between an input edge and an output edge of the operational amplifier 1. The control circuit 3 generates a plurality of control voltages based on a gain control signal and having offsets according to input/output DC component differences of the operational amplifier 1 and supplies each of the plurality of control voltages to each of the plurality of variable resistance elements 21 and 22. COPYRIGHT: (C)2011,JPO&INPIT
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