| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable gain amplifier having an offset removing circuit and capable of cancelling an offset favorably by removing offset fluctuation at a gain change. SOLUTION: The amplifier comprises a gain-variable main amplifier circuit (11) for amplifying the difference signal between an input signal and a feedback signal, a gain-variable feedback amplifying circuit (12) for amplifying an output signal from the main amplifying circuit to generate the feed back signal, and a gain control circuit (13) for changing a gain of the main amplifying circuit and complementarily changing a gain from the feedback amplifying circuit.
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