| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifier which can suppress deterioration of distortion (CSO and CTB) without deteriorating C/N and can be adjusted extremely easily and accurately. SOLUTION: This amplifier has a gain control circuit 2 arranged in an amplifier 3 composed of amplifying circuits 1a to 1d, and the gain changeover switch 5 is arranged which is configured to select and switch one of the amplifying circuit 1a disposed on the signal input side of the gain control circuit 2, a fixed attenuating circuit 4a which attenuates an input signal by 3 dB and a fixed attenuating circuit 4b which attenuates it by 5 dB, and a path circuit 4c which passes the signal without attenuation, the circuits 4a and 4b being between the amplifying circuit 1a and gain control circuit 2. COPYRIGHT: (C)2004,JPO
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