Noise reducing system for video signal

摘要

A noise reducing system for a video signal comprises a vertical pre-emphasis circuit supplied with an input video signal which is to be transmitted, for supplying an output signal to a transmission system, and a vertical de-emphasis circuit supplied with the video signal which has been pre-emphasized in the vertical pre-emphasis circuit and has been transmitted through the transmission system. The vertical pre-emphasis circuit has a characteristic for relatively emphasizing the level of high-frequency components of the input video signal having spatial frequencies in a vertical direction of a picture, compared to low-frequency components of the input video signal. On the other hand, the vertical de-emphasis circuit has a characteristic for relatively attenuating the level of the high-frequency components of the pre-emphasized video signal having spatial frequencies in the vertical direction of the picture, compared to the low-frequency components of the pre-emphasized video signal. The characteristics of the vertical pre-emphasis circuit and the vertical de-emphasis circuit cooperate so as to reduce noise having high spatial frequencies in the vertical direction of the picture.