PURPOSE: To make a glass delay line unnecessary, to display excellent noise removing effects without deteriorating signals and simplify a circuit such as semiconductors etc., and to miniaturize the device by performing a 1H delay by using a digital memory.

CONSTITUTION: FM luminance signals inputted from an input terminal 11 are demodulated to signals of base band by a demodulator 12 and then converted to digital signals by an A/D convertor, digitalized luminance signals are 1H-delayed by a 1H digital memory 14 and added to a subtracter 15 and fifference from the original signal is taken. The signals are compared with the specified reference level, and when there is linear correlation, a switch 17 is closed. Outputs of the switch 17 are applied to a subtracter 19 through a 1/2 attenuator 18, and subtraction between output signals of the A/D convertor 13 is made. Outputs of the subtracter 19 are D/A converted and led to an output terminal 21.