| 摘要 |
PURPOSE:To obtain a quintic low-pass filter which is reduced in power consumption and size by using switched capacitor circuits as resistance elements of an impedance converting circuit having frequency dependency. CONSTITUTION:Resistance circuits 22, 24, 25, 27, 28 31-34, 37, etc., consisting of switched capacitor circuits are connected between an input terminal 21 and an output terminal 36. Those resistance circuits are each constituted by connecting one terminal of a switch 42 which is controlled by a clock pulse phiB to one terminal of a switch 41 which is supplied at the other terminal with a signal and controlled by a clock pulse phiA and further connecting one terminal of a switch 44 which is controlled by the pulse phiB to one terminal of a switch 43 which outputs a signal from the other terminal and controlled by the pulse phiA. Then, capacitors Cg1-Cg10 are connected between the connection points of the switches 41 and 42 and the connection point of the switches 43 and 44. Those circuits operate as resistance elements having specific equivalent resistance values according to the frequencies of the pulses phiA and phiB and the values of the capacitors Cg1-Cg10. |
