PURPOSE: To reduce a noise level by turning on/off two MOS switches of a reproducer at a prescribed section I , and inverting them at a prescribed section IIso as to cancel or suppress the input noise generated from an MOS operational amplifier.

CONSTITUTION: A section where the MOS switch 15 of a multiplexer is turned o on and the MOS switch 16 is turned off is taken as the section I , and a section where the switch 15 is turned off an the switch 16 is turned on is taken as the section II. An SC integration device being the basic building block of an SCF is provided with an MOS operational amplifier 26. An output signal of the integration device is an input signal added with a noise signal generated from the amplifier 26 itself at the section I and is a noise signal generated from the amplifier 26 itself at the section II. An MOS switch 29 of a reproduce is turned on and an MOS switch 30 is turned off at the section I , the input signal is inputted to a summing input of a subtractor 33 and the switch 29 is turned off and the switch 30 is turned on at the section II, and the input signal is inputted to a subtraction input of the subtractor 33. Only a transmission subtracting the noise signal from the output signal added with the noise signal is outputted by repeating the operation above.