Digital noise reducing apparatus for a video signal processing recording reproducing apparatus

Claim 1

A video signal processing apparatus comprising: an analog to digital converting means for converting an input luminance signal to a digital signal; a single digital delaying means for delaying said digital signal by a predetermined period; a switch means having an output terminal connected to an input terminal of said digital delaying means, and first and second input terminals respectively connected to an output terminal of said analog to digital converting means and output terminal of said switch means being normally connected to said first input terminal and to said second input terminal in response to an externally provided signal indicating an occurrance of a dropout in said input luminance signal; a first calculating means for producing a first difference signal between input and output digital signals of said digital delaying means; an attenuating means for attenuating, by a predetermined ratio, said first difference signal from said first calculating means so as to produce an attenuated first calculating means so as to produce an attenuated first difference signal; a limiting means for limiting within a predetermined level the amplitude of said attenuated first difference signal so as to produce an attenuated and limited first difference signal; a second calculating means for producing a second difference signal between said input digital signal of said digital delaying means and said attenuated and limited first difference signal; and a digitial to analog converting means for converting said second difference signal from said second calculating means, so as to thereby obtain a dropout compensated luminance signal when said dropout occurs and a noise cancelled luminance signal in the absence of the occurrance of said dropout.