| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable gain amplifier system that can accurately obtain a desired overall gain and avoid a deteriorated distortion characteristic, increase in the total noise figure and increase in the power consumption. SOLUTION: The variable gain amplifier system is provided with a 1st amplifier circuit (A) that can control its gain during operation, a 2nd amplifier circuit (B) that is coupled with an output of the 1st amplifier circuit (A) and fixes its gain during the operation and a 3rd amplifier circuit (C) that is coupled with an output of the 2nd amplifier circuit (B) and can control its gain during the operation.
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