| 摘要 |
PROBLEM TO BE SOLVED: To obtain a satisfactory frequency characteristic of an output signal even in the case of selecting a different gain resistor in a semiconductor amplifier circuit for switching gain resistors of an amplifier in accordance with a signal level. SOLUTION: This amplifier circuit is provided with an amplifier 4, a plurality of resistors 10 and 11 for determining an amplification rate of the amplifier 4, a first switching means 12 for switching the plurality of resistors 10 and 11, an output circuit 5 for outputting a signal amplified by the amplifier 4, and a second switching means for switching output resistance values of the output circuit 5 in interlock with the first switching means 12 in accordance with the signal to be outputted. COPYRIGHT: (C)2008,JPO&INPIT
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