| 摘要 |
PROBLEM TO BE SOLVED: To provide a filter circuit that operates at high-speed as a Gm-C filter, has a wide range of an input voltage in the same way an RC active filter, has excellent linear performance, and suppresses variation of a characteristic as well as or more than the Gm-C filter. SOLUTION: The filter circuit includes: a filter 100 including an operational amplifier 101 having an inverting input terminal 104, a non-inverting input terminal 103, and an output terminal 106; and a filter control signal generation circuit 102 for generating a filter control signal for controlling the filter. The filter control signal generation circuit 102 generates the filter control signal for controlling a GB product of the operational amplifier 101 and a second pole frequency, supplies the filter control signal to the operational amplifier 101, and controls the cutoff frequency and the quality factor of the filter 100. COPYRIGHT: (C)2011,JPO&INPIT
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