| 摘要 |
An integrated voltage control variable gain circuit capable of exhibiting, when the external circuit network is connected in a first configuration, a low distortion factor of the output signal, and capable of effecting, when the external circuit network is connected in a second configuration, independent controls of gains for different two input signals. The integrated voltage control variable gain circuit is provided, in its integrated part, with a first operational amplifier circuit, a second operational amplifier circuit, a third operational amplifier circuit, a fourth operational amplifier circuit, a fifth operational amplifier circuit, a first gain control section and a second gain control section. The first operational amplifier circuit, the first gain control section and the third operational amplifier circuit are arranged in a first signal line, while, in the second signal line, arranged are the second operational amplifier circuit, the second gain control section and the fourth operational amplifier circuit. It is possible to select whether the fifth operational amplifier circuit is disposed on the second signal line, by selecting the configurations of the external circuit network.
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