Showing papers on "Comb generator published in 1978"

Comb filter system

Abstract: In apparatus for playback of a video disc record bearing chrominance information recorded in "buried subcarrier" format, a comb filter involving subtractive combination of the input and output of a 1H delay line is used to separate chrominance component of recorded composite signal from accompanying luminance signal. Separated chrominance component is subject to demodulation to obtain color difference signals, which are applied to a SECAM modulator to obtain SECAM format signal for delivery to SECAM type color TV receivers. To reduce "cross-color" effects of diagonal luminance components, a second comb filter is interposed between first comb filter and color demodulators. Second comb filter employs 1H delay line with receiving end misterminated by a short circuit termination to obtain reflection effect. Signal at sending end, comprising sum of input composite signal and reflected, 2H delayed signal is matrixed with undelayed composite signal to obtain effect of comb filter with recurring peaks separated by half line frequency (f H /2) intervals.