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Abstract

An in-band television signal scrambling method and apparatus are disclosed which employ a scrambler which receives and scrambles a television signal and one or more descramblers for restoring the scrambled television signal to an unscrambled condition. A tier level encoding scheme is used to identify and render operative predetermined descramblers. The scrambler encodes tier level coding information in the form of whiter-than-white pulses on a scrambled television signal, these pulses being detected by the descramblers, with only those descramblers identified by the tier level coding information being rendered operative to unscramble the scrambled television signal. The descramblers preferably employ a plug-in module into which the tier level coding information assigned to a particular scrambler can be programmed. The scrambling operation may be accomplished by suppressing the amplitude of the horizontal synchronizing signals in a television signal, and generating timing pulses in the form of other whiter-than-white pulses in the scrambled television signal which cue the descramblers enabling them to reconstruct the suppressed amplitude horizontal synchronizing signals.

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First Claim