| 摘要 |
PROBLEM TO BE SOLVED: To realize a balanced gain control amplifier capable of obtaining satisfactory performance even with low power supply voltage. SOLUTION: There are provided a differential amplification circuit 1 composed of first and second transistors 1a, 1b with collectors connected to power supply resistors 1c, 1d and with emitters connected with each other, and third and fourth transistors with bases connected with each other for controlling gains of the first and second transistors 1a, 1b. The first transistor and the third transistor are connected with each other in their collectors and emitters, and the second transistor and the fourth transistor are connected with each other in their collectors and in their emitters. A balancing signal is inputted between the bases of the first transistor and the second transistor, and a gain control voltage is inputted to the base of the third transistor and to the base of the fourth transistor. COPYRIGHT: (C)2004,JPO
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