Selective off-premises jamming for premium CATV service

Claim 1

A method for operating a CATV system comprising the steps of: transmitting video signals on a first transmission line from a head end to each of a plurality of distribution locations; transmitting the video signals on a plurality of second transmission lines from each of the distribution locations to each of a plurality of subscriber locations; each video signal being transmitted on a TV channel of the first and second transmission lines; certain ones of said video signals being premium signals which are each transmitted on a premium TV channel; determining which of the premium video signals each subscriber is entitled to receive; transmitting a jamming signal on those premium TV channels of each second transmission line which carry a premium video signal which a corresponding subscriber is not entitled to receive; and refraining from transmitting a jamming signal on those TV channels of the second transmission lines which carry a premium video signal which the corresponding subscriber is entitled to receive, different jamming signals being transmitted on different ones of said second transmission lines from each distribution location, thereby to permit different subscribers to receive different TV channels via each distribution location, the method characterized by the steps of: generating at each distribution location a plurality of first jamming signals, each having a different frequency corresponding to a frequency of one of the premium channels; providing remotely controlled switched networks at each distribution location: directing the first jamming signals through the switched networks of each distribution location; the transmission of the first jamming signals through the switched networks being independent of the video signals; controlling the switched networks from the head end to prevent transmission therethrough of certain first jamming signals having frequencies corresponding to those premium video signals which certain subscribers are entitiled to receive; deriving from the switched networks second jamming signals containing frequencies corresponding to those first jamming signals allowed to be transmitted through such switched networks; combining at each distribution location, independent of the video signal, those jamming signals to be transmitted to each subscriber; and combining at each distribution location a second jamming signal derived from the switched networks with said video signals for transmission on each second transmission line to a subscriber location such that each subscriber coherently receives those premium video signals to which he is entitled, while those to which he is not entitled are jammed by said second jamming signal; all of said second jamming signals transmitted to different subscribers from each distribution location being derived from said first jamming signals generated at such distribution location.

Claim 2

A method for operating a CATV system comprising the steps of: transmitting video signals on a first transmission line from a head end to each of a plurality of distribution locations; transmitting the video signals on a plurality of second transmission lines from each of the distribution locations to each of a plurality of subscriber locations; each video signal being transmitted on a TV channel of the first and second transmission lines; certain ones of said video signals being premium signals which are each transmitted on a premium TV channel; determining which of the premium video signals each subscriber is entitled to receive; transmitting a jamming signal on those premium TV channels of each second transmission line which carry a premium video signal which a corresponding subscriber is not entitled to receive; and refraining from transmitting a jamming signal on those TV channels of the second transmission lines which carry a premium video signal which the corresponding subscriber is entitled to receive, different jamming signals being transmitted on different ones of said second transmission lines from each distribution location, thereby to permit different subscribers to receive different TV channels via each distribution location, the method characterized by the steps of: generating at each distribution location a plurality of first jamming signals, each having a different frequency corresponding to a frequency of one of the premium channels; providing remotely controlled switched networks at each distribution location: directing the first jamming signals through the switched networks of each distribution location; the transmission of the first jamming signals through the switched networks being independent of the video signals; controlling the switched networks from the head end to prevent transmission therethrough of certain first jamming signals having frequencies corresponding to those premium video signals which certain subscribers are entitiled to receive; deriving from the switched networks second jamming signals containing frequencies corresponding to those first jamming signals allowed to be transmitted through such switched networks; combining at each distribution location, independent of the video signal, those jamming signals to be transmitted to each subscriber; and combining at each distribution location a second jamming signal derived from the switched networks with said video signals for transmission on each second transmission line to a subscriber location such that each subscriber coherently receives those premium video signals to which he is entitled, while those to which he is not entitled are jammed by said second jamming signal; all of said second jamming signals transmitted to different subscribers from each distribution location being derived from said first jamming signals generated at such distribution location.

Claim 6

A method for delivering from a head end of a CATV system to a plurality of subscribers a plurality of premium TV signals such that, during a prescribed time period of operation, each subscriber receives for his use only those premium TV signals to which he is entitled, said method comprising the steps of: assigning to different subscribers various premium video frequencies corresponding to the different premium TV signals such subscribers are entitled to receive; transmitting the premium TV signals as separate video frequencies to a plurality of distribution locations, each distribution location being connected by each of a plurality of subscriber lines to each of a plurality of subscriber locations; applying at each distribution location different jamming signals to different subscriber lines connected to such distribution location comprising the step of generating at each of the distribution locations a plurality of first jamming signals of different frequencies, each first jamming signal having a substantially fixed frequency sufficiently near a corresponding video frequency to render a video signal at such frequency unreceivable by a subscriber, each first jamming signal being generated substantially continuously during the prescribed time period of operation; combining the first jamming signals at each distribution location; controlling from the head end the delivery of the first jamming signals to develop a second jamming signal that does not include frequencies corresponding to any premium TV signals that a corresponding subscriber is entitled to receive; and combining each second jamming signal with all of the premium TV signals for transmission on each subscriber line to the subscriber locations such that the second jamming signal for each subscriber line jams only those premium TV signals to which the subscriber is not entitled, the adding being done at the distribution locations; all of said second jamming signals transmitted to different subscribers from each distribution location being derived from said first jamming signals generated at such distribution location.

Claim 7

A method for delivering from a head end of a CATV system to a plurality of subscribers a plurality of premium TV signals such that, during a prescribed time period of operation, each subscriber receives for his use only those premium TV signals to which he is entitled, said method comprising the steps of: assigning to different subscribers various premium video frequencies corresponding to the different premium TV signals such subscribers are entitled to receive; transmitting the premium TV signals as separate video frequencies to a plurality of distribution locations, each distribution location being connected by each of a plurality of subscriber lines to each of a plurality of subscriber locations; applying at each distribution location different jamming signals to different subscriber lines connected to such distribution location comprising the step of generating at each of the distribution locations a plurality of first jamming signals of different frequencies, each first jamming signal having a substantially fixed frequency sufficiently near a corresponding video frequency to render a video signal at such frequency unreceivable by a subscriber, each first jamming signal being generated substantially continuously during the prescribed time period of operation; combining the first jamming signals at each distribution location; controlling from the head end the delivery of the first jamming signals to develop a second jamming signal that does not include frequencies corresponding to any premium TV signals that a corresponding subscriber is entitled to receive; and combining each second jamming signal with all of the premium TV signals for transmission on each subscriber line to the subscriber locations such that the second jamming signal for each subscriber line jams only those premium TV signals to which the subscriber is not entitled, the adding being done at the distribution locations; all of said second jamming signals transmitted to different subscribers from each distribution location being derived from said first jamming signals generated at such distribution location.

Claim 17

A method for delivering from a head end of a CATV system to a plurality of subscribers a plurality of premium TV signals such that each subscriber receives for his use only those premium TV signals to which he is entitled, said method comprising the steps of: transmitting the premium TV signals as separate video frequencies to a plurality of distribution locations, each distribution location being connected by each of a plurality of subscriber lines to each of the plurality of subscriber locations; generating at each of the distribution locations a plurality of first jamming signals of different frequencies each corresponding in frequency to one of the separate video frequencies; combining all of the first jamming signals at each distribution location, said combining being independent of any of the premium TV signals; delivering the combined first jamming signals to each of a plurality of groups of controllable filter devices, each filter device group corresponding to one of the subscribers; controlling from the head end the first jamming frequency that may be passed by each group of controllable filter devices; using the filter devices to derive from the combined first jamming signals only those jamming signals which correspond to video frequencies to which the subscriber corresponding to such filter group is not entitled to receive, thereby to develop a second jamming signal; and adding the second jamming signal to all of the premium TV signals for transmission on each subscriber line to the subscriber locations such that the second jamming signal for each subscriber line jams only those premium TV signals to which the subscriber is not entitled, the adding being done at the distribution locations; different second jamming signals being applied to different subscriber lines at each distribution location; all of said second jamming signals transmitted to different subscribers from each distribution location being derived from said first jamming signals generated at such distribution location.

Claim 18

A method for delivering from a head end of a CATV system to a plurality of subscribers a plurality of premium TV signals such that each subscriber receives for his use only those premium TV signals to which he is entitled, said method comprising the steps of: transmitting the premium TV signals as separate video frequencies to a plurality of distribution locations, each distribution location being connected by each of a plurality of subscriber lines to each of the plurality of subscriber locations; generating at each of the distribution locations a plurality of first jamming signals of different frequencies each corresponding in frequency to one of the separate video frequencies; combining all of the first jamming signals at each distribution location, said combining being independent of any of the premium TV signals; delivering the combined first jamming signals to each of a plurality of groups of controllable filter devices, each filter device group corresponding to one of the subscribers; controlling from the head end the first jamming frequency that may be passed by each group of controllable filter devices; using the filter devices to derive from the combined first jamming signals only those jamming signals which correspond to video frequencies to which the subscriber corresponding to such filter group is not entitled to receive, thereby to develop a second jamming signal; and adding the second jamming signal to all of the premium TV signals for transmission on each subscriber line to the subscriber locations such that the second jamming signal for each subscriber line jams only those premium TV signals to which the subscriber is not entitled, the adding being done at the distribution locations; different second jamming signals being applied to different subscriber lines at each distribution location; all of said second jamming signals transmitted to different subscribers from each distribution location being derived from said first jamming signals generated at such distribution location.