| 摘要 |
PROBLEM TO BE SOLVED: To provide a switched capacitor filter circuit which reduces feedthrough noise. SOLUTION: The circuit is provided with a first noise compensating transistor 108 whose drain and source are connected to a switching transistor 101 to which a switching control signalϕ1 is inputted, and the inverting input terminal of an operational amplifier 113 is connected. Short-circuited source and drain terminals are connected to the inverting input terminal of an operational amplifier 113, and a signal having a polarity reverse to the control signalϕ1 is inputted to the compensating transistor 108. Feedthrough noise having a polarity reverse to feedthrough noise generated in the switching transistor 101 is generated by the compensating transistor 108, and canceled. COPYRIGHT: (C)2004,JPO
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