Luminance signal/color signal separating circuit and noise reduction circuit using a comb filter

摘要

A luminance signal/color signal separating circuit comprises a comb filter for Y/C separation. The addition output of the comb filter comprises a luminance signal component, while the subtraction output comprises a color signal component and non-correlation components of a luminance signal. The non-correlation components in the subtraction output are extracted by a trap circuit and added to the addition output of the comb filter. Accordingly, the degradation of vertical direction resolution of reproduced signal will be prevented. Also, under some circumstances, the extracted non-correlation components are previously enhanced before being added to the luminance signal. The noise reduction circuit in reproduction mode shares the above comb filter for color signal separation. When dropout occurs, the color signal in the output of the 1H delay circuit of the comb filter is inverted and separated to be used as a drop out compensation signal.