| 摘要 |
PROBLEM TO BE SOLVED: To reduce field through noise as much as possible even when a feedback capacitance is reduced or when there is a process error etc. SOLUTION: A switched capacitor filter includes an operational amplifier 2, a feedback capacitor 8 provided between the inverse input terminal of the operational amplifier 2 and the output terminal of the operational amplifier 2, and a switching transistor 9 provided between the inverse input terminal of the operational amplifier 2 and the output terminal of the operational amplifier 2. Further, the filler is constituted such that two or more transistors 14-18 for noise compensation are connected to the inverse input terminal of the operational amplifier 2. In the case of this configuration, the field through noise can be reduced sufficiently by suitably regulating each size of two or more transistors for the noise compensation. COPYRIGHT: (C)2006,JPO&NCIPI
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