Patent ID: 6349139
Filing Date: 2002-02-19
Classification: H04N

Abstract:
A method of minimizing chroma subcarrier instability in a line scrambled video signal, wherein the chrominance signal is imperfectly separated from the luminance signal to produce a scrambled chrominance signal having stable chroma and a luminance signal containing stable residual chroma before the scrambling process but unstable residual chroma after the scrambling process, characterized by the steps of:coring the luminance signal before or after scrambling at a selected level to limit passage of the unstable residual chroma in the luminance signal when the level of the unstable residual chroma is less than the selected level while allowing passage of signals of levels greater than the selected level, to provide a scrambled luminance signal with minimized unstable residual chroma; and summing the scrambled chrominance signal having stable chroma with the scrambled luminance signal with minimized unstable residual chroma to provide the line scrambled video signal with minimized chroma subcarrier instability.