Video noise reduction circuit

Abstract

A noise reduction circuit comprises a high pass filter for extracting a signal component containing noise from an input signal, a variable level limiter for limiting the level of the signal component extracted by the filter to produce a noise suppressing signal, and a level adjustor for adjusting the level of the noise suppressing signal. A level detector detects the level of the input signal, and a control signal generator generates first and second control signals based on the detected output of the level detector, supplies the first control signal to the level limiter so as to control the limit level thereof, and supplies the second control signal to the level adjustor so as to control the gain thereof. In a signal subtracter, the noise suppressing signal from the level adjustor is added with reversed polarity to the input signal to suppress the noise contained in the input signal and thereby produce a low-noise output signal.