| 摘要 |
An object of the present invention is to provide a filter circuit which improves NF of a Gm-C filter. The filter circuit comprises a filter comprising at least one first operational transconductance amplifier whose mutual conductance varies depending on a first control signal and a first capacitor, a second operational transconductance amplifier whose mutual conductance is controlled by the first control signal, a third operational transconductance amplifier whose mutual conductance is controlled by a second control signal, and a second capacitor connected to output terminals of the first and second operational transconductance amplifiers and input terminals of the filter.
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