Patent ID: 6278495
Filing Date: 2001-08-21
Classification: H04N

Abstract:
A digital comb filter for separating luma and chroma information from a composite video signal, comprising:a band split filter circuit to generate 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 for combining samples alternately from a high pass tap and a low pass tap into a single data stream;a plurality of line delays for delaying a current line of video to provide a plurality of line taps for the digital comb filter from a plurality of surrounding lines of video;a plurality of field delay memories to provide a plurality of field delay and frame delay taps to the digital comb filter;a line comparison circuit for comparing a plurality of band split taps to determine a similarity or a difference between the plurality of surrounding lines of video and the current line;a field and frame comparison circuit for determining the coefficients of the field and frame delay taps of the digital comb filter and a value of the coefficients of the current video line and an in-phase line from the field delay; anda logic circuit for scaling and summing a plurality of high pass taps of the surrounding lines of video and generating chroma and high pass luma from the plurality of high pass taps of the surrounding lines of video and the current line of video.