Selective off-premises jamming for premium CATV service

摘要

Selective off-premises jamming for premium CATV service is provided by using continuously running fixed-frequency oscillators (19.1- 19.n) for generating jamming signals at each of a plurality of distribution locations (13). The frequency of each oscillator corresponds to the frequency of one of the premium channels. A remotely controlled switched network is provided at each distribution location for applying jamming signals only to those TV channels of the subscriber lines (14) upon which the corresponding subscriber (15) is not entitled to receive premium signals. Since jamming signals are not applied to the TV channels upon which subscribers are entitled to receive premium TV programs, there is no need for de-scrambling apparatus at the various subscriber locations. In various embodiments, the switched network may be an array of switches (20.1-20.n), an array of filter traps (32.1-32.n) or an array of parallel connected band-pass filters (41.1-41.n).