EDGE NOISE CANCELLER CIRCUIT

摘要

PURPOSE:To form an effective noise canceller by using a 1st edge noise elimination circuit so as to eliminate a high frequency noise of the edge of a longitudinal line through the noise detection and increasing the attenuation of a comb-line filter for a Y signal only when longitudinal edge information exists so as to eliminate duplicatedly the edge noise. CONSTITUTION:An emphasis circuit 1 emphasizes an input signal and extracts the edge while slicing the peak of the white and dark level of the emphasis signal to extract a noise of the edge by an HPF 3. It is subtracted by a subtractor 4 to eliminate a 1st noise. Then a 1H delay line 5 and a subtractor 6 extract a difference component thereby setting a level in such a degree that a high frequency noise of the edge passes through the level of a limiter 7. Then a coefficient device 8 multiplies it by K to take a difference with an original signal by a subtractor 9 thereby constituting the comb-line filter for a Y signal capable of eliminating the high frequency noise. Since only the duplicated noise is eliminated duplicatedly, the effective edge noise canceller is constituted without losing the detail of the signal.