Optimum amplitude and frequency of jamming carrier in interdiction program denial system

摘要

Off premises cable television interdiction apparatus comprises a microprocessor actuation and control means for actuating and controlling one or more frequency agile voltage controlled oscillators. The voltage controlled oscillators selectively jam only unauthorized premium programming transmitted in the clear from a headend to a particular subscriber. Each voltage controlled oscillator is allocated a continuous band of frequencies consistent with the elimination of jamming signal frequency harmonics which may disturb authorized programming at a higher channel frequency. The microprocessor actuation and control means provides a calibration mode and a normal mode of operation. The method of interdiction comprises the steps of generating and storing voltage control words for operating the oscillators consistent with a head end selected jamming factor for a particular channel to be jammed and addressably transmitted and stored premium programming authorization data. An optimum frequency amplitude window for the jamming signal is disclosed.