SYNC SUPPRESSED VIDEO SIGNAL DESCRAMBLER CIRCUIT: DETECTING CYCLIC COLOUR BURST ABSENCES AND OCCURRENCES

摘要

A timing signal generator for recovering timing signals in scrambled video signals in which the synchronizing signals are suppressed includes a tuned detector responsive to the color burst signal contained in the back porch of the suppressed horizontal blanking pulse. The vertical interval is detected as the absence of color burst for a specified time interval, and horizontal sync information is obtained by the detection of the first color burst after an absence of color burst.