Patent ID: 6462790
Filing Date: 2002-10-08
Classification: H04N

Abstract:
A digital comb filter for separating luma and chroma information from a composite video signal, comprising:a filter circuit that generates a signature signal by which each line of video can be correlated, the signature signal having a low pass band that contains only luma, and a high pass band that contains both chroma and high frequency luma; a multiplexer that combines high pass band and low pass band samples alternately from the filter circuit into a single data stream; a plurality of delay circuits that provides a plurality of line taps, field delays, and frame delay taps for the digital comb filter; a plurality of comparison circuits that compare a plurality of filter taps and determine a plurality of coefficients for the plurality of field and frame delay taps of the digital comb filter; a logic circuit that scales and sums a plurality of high pass taps of the surrounding lines of video and generates chroma and high pass luma from the plurality of high pass taps of the surrounding lines of video and a current line of video; and a dynamic thresholding circuit that suppresses unwarranted comb filter failures in the presence of luma edges.