| 摘要 |
A method and apparatus, for jamming selected channels, in a CATV system, wherein six different pre-determined frequencies ("fx"), are generated at a head end, on a time divisional basis, which head end also generates a sychrinization signal "sync. sig.") that identifies which fx is being generated, a multiple of receiver ends, each of which receives, at one input all of the TV channels' signals, the fx, the sync. sig., and a subscriber status signal ("SSS") that identifies the channels, if any, that the subscriber is entitled to receive, wherein the receiver end: (A) divides the received signals into: (I) TV channels' signals, SSS, and sync. sig., and (II) fx; (B) generates a local fixed frequency; (c) mixes the local fixed frequency with the fx, thereby creating a jamming signal; (D) decodes the sync. sig.; (E) decodes the SSS, to obtain the subscriber status information; (F) transmittes the TV channels' signals to the subscriber, if the subscriber status information, indicates that subscriber, is entitled to receive at least some or all of the TV channels; and (G) combines the jamming signal, with the TV signals, going to the subscriber, when the created jamming signal, is for a channel, that subscriber is not entitled to receive.
|
