| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiple feedback type BPF circuit capable of preventing the circuit from being oscillated or noise from being increased near a resonant frequency even if a Q factor is great. SOLUTION: A multiple feedback type BPF circuit includes: an operational amplifier 15 of which a non-inverted input terminal is grounded; an external input terminal 11 which is connected to an inverted input terminal of the operational amplifier 15 via an input capacitor 13 and a resistance element 14 connected in series and to which an input signal is supplied; a first feedback route A1 for feeding output of the operational amplifier 15 back to the inverted input terminal via a first feedback path capacitor 16; and a second feedback route A2 for feeding the output of the operational amplifier 15 back to a connecting point B1 between the input capacitor 13 and the resistance element 14 via a second feedback path resistance element 17 and a second feedback path capacitor 18 connected in parallel. COPYRIGHT: (C)2009,JPO&INPIT
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