Patent ID: 6292567
Filing Date: 2001-09-18
Classification: H04N

Abstract:
A television transmission system, comprising:means for scrambling a television signal by suppressing at least one of the horizontal sync pulse and vertical blanking interval of the television signal;means for transmitting the scrambled television signal;means for generating, and separately transmitting along with the scrambled television signal, a pilot carrier that includes timing information corresponding to said at least one of the horizontal sync pulse and vertical blanking interval; andmeans for descrambling the scrambled television signal including means for receiving the pilot carrier and means for periodically suppressing, in accordance with the timing information included in the pilot carrier, video information of the television signal to an extent whereby said at least one of the horizontal sync pulse and vertical blanking interval becomes detectable by a television receiver;wherein said means for descrambling comprises a frequency selective notch filter in electrical communication with an RF throughpath, and means for moving the center frequency of said notch filter.