摘要 |
A variable gain amplifier is disclosed, comprising a pair of differential MOS transistors M1 and M2 and a current mirror. The sources of the differential MOS transistors M1 and M2 are connected to a constant voltage terminal. Since a DC voltage Vc is added to input signals, output signals that are theoretically free of a distortion are obtained. The gain can be controlled from infinitesimal. Since the gain is directly proportional to the control voltage, it can be easily controlled. Since a single output current is free of a distortion, even if amplifiers are connected on many stages, an output signal that is free of a distortion can be obtained.
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