| 摘要 |
A variable gain amplifier circuit includes an emitter-grounded amplifier circuit and an emitter follower connected to the input section of the emitter-grounded amplifier circuit and having a variable output impedance. In a gain control method for the variable gain amplifier circuit, a bias voltage applied to the input section of the emitter-grounded amplifier circuit is kept constant, and the output impedance of the emitter follower is changed in a direction in which the gain of the emitter-grounded amplifier circuit decreases.
|
