Subscriber site method and apparatus for decoding and selective interdiction of television channels
First Claim
1. Subscriber site apparatus useful in a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band synchronously related to said synchronization components, and wherein each of said channel signals is encoded in accordance with a common encoding rule, said subscriber site apparatus comprising:
- a data receiver responsive to at least one of said channel signals for recovering said common timing reference signal; and
a single broadband apparatus operable over said RF band and responsive to said recovered common timing reference signal for simultaneously decoding all of said channel signals in accordance with the inverse of said encoding rule to provide multiple decoded channel signals suitable for direct simultaneous application to a conventional television receiver.
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Accused Products
Abstract
An decryption system which facilitates simultaneous decryption of multiple encrypted television channel signals thus making them simultaneously available for direct tuning in television receivers. The system is characterized by the utilization of a plurality of channel signals time synchronized with respect to a common timing reference signal. Each channel signal is encrypted in accordance with a predetermined encoding rule and distributed to subscriber sites where an unencrypted block of channel signals are made simultaneously available by decrypting them synchronously with the recovered timing reference signal in accordance with the inverse of the encoding rule. An interdiction apparatus then selectively jams a plurality of television channels from within the unencrypted block of channel signals thus making it possible for a provider to programmably interdict reception of selective channels by unauthorized subscribers. The invention can be advantageously used in both over-the-air and cable subscription television distribution systems to provide subscribers with a plurality of simultaneously available decrypted television signals and selectively encrypted channels, e. g., premium channels.
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Citations
40 Claims
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1. Subscriber site apparatus useful in a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band synchronously related to said synchronization components, and wherein each of said channel signals is encoded in accordance with a common encoding rule, said subscriber site apparatus comprising:
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a data receiver responsive to at least one of said channel signals for recovering said common timing reference signal; and a single broadband apparatus operable over said RF band and responsive to said recovered common timing reference signal for simultaneously decoding all of said channel signals in accordance with the inverse of said encoding rule to provide multiple decoded channel signals suitable for direct simultaneous application to a conventional television receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 40)
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9. Subscriber site apparatus useful in a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band and synchronous with said synchronization components, and wherein each of said channel signals is encrypted in accordance with a common encoding rule, said subscriber site apparatus comprising:
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a timing recovery circuit responsive to said common timing reference signal for generating a common sync signal; a single decoder responsive to said common sync signal for simultaneously decrypting all of said channel signals in accordance with the inverse of said encoding rule to generate multiple decrypted channel signals, each capable of directly causing a conventional television receiver to produce an intelligible image; and an interdiction apparatus for periodically inserting a jamming signal into at least one of said multiple decrypted channel signals to render it incapable of directly causing said television receiver to produce an intelligible image. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method of selectively scrambling television channels from an encrypted multichannel television signal at a subscriber site, comprising the steps of:
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simultaneously decrypting said encrypted multichannel television signal to form a decrypted multichannel television signal; determining an interfering frequency for a selected television channel signal according to an interdiction table containing data related to a plurality of channel signals selected to be scrambled; commanding a frequency generator to generate an output of said interfering frequency; waiting until said frequency generator has locked to said interfering frequency; enabling combining of said output of said frequency generator with said decrypted multichannel television signal; dwelling for a predetermined time period to scramble said selected television channel signal; disabling combining of said output of said frequency generator from said decrypted multichannel television signal; and cyclically repeating said previously recited steps for a next selected television channel signal. - View Dependent Claims (18)
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19. Subscriber site apparatus useful in a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band and synchronous with said synchronization components, and wherein each of said channel signals is encrypted in accordance with a common encoding rule, said subscriber site apparatus comprising:
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an interdiction apparatus for periodically inserting a jamming signal into said RF band to generate an interdicted RF signal; a timing recovery circuit responsive to said common timing reference signal for generating at least one sync signal; and a single decoder responsive to said sync signal and said interdicted RF signal to simultaneously decrypt multiple channel signals in accordance with the inverse of said encoding rule to generate a recovered multichannel signal comprising multiple decrypted channel signals capable of directly causing a conventional television receiver to produce an intelligible image and at least one scrambled channel signal incapable of directly causing said television receiver to produce an intelligible image.
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20. A method of distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, said method comprising the steps of:
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generating at said headend multiple carrier signals; modulating at said headend each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; generating a common timing reference signal synchronous with said time coincident synchronization components; causing each of said channel signals to be encrypted at said headend in accordance with a common predetermined encoding rule; modulating a selected encrypted channel signal in response to said common timing reference signal; distributing said multiple encrypted channel signals from said headend to said subscriber sites as a common RF signal; responding at each subscriber site to said common timing reference signal to simultaneously decrypt all of the channel signals distributed thereto by operating upon said common RF signal with a single decoder in accordance with the inverse of said encoding rule to generate multiple decrypted channel signals, each capable of directly causing a conventional television receiver to produce an intelligible image; and periodically inserting at each subscriber site a jamming signal into at least one of said multiple decrypted channel signals to render it incapable of directly causing said television receiver to produce an intelligible image.
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21. A method of distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, said method comprising the steps of:
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generating at said headend multiple carrier signals; modulating at said headend each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; generating a common timing reference signal synchronous with said time coincident synchronization components; causing each of said channel signals to be encrypted at said headend in accordance with a common predetermined encoding rule; modulating a selected encrypted channel signal in response to said common timing reference signal; distributing said multiple encrypted channel signals from said headend to said subscriber sites as a common RF signal; periodically inserting a jamming signal at each subscriber site corresponding to at least one encrypted channel signal into said common RF signal to generate an interdicted RF signal; and responding at each subscriber site to said common timing reference signal and said interdicted RF signal to simultaneously decrypt multiple channel signals distributed thereto with a single decoder in accordance with the inverse of said encoding rule to generate multiple decrypted channel signals capable of directly causing a conventional television receiver to produce an intelligible image and at least one scrambled channel signal incapable of directly causing said television receiver to produce an intelligible image.
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22. Apparatus for distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, the apparatus comprising:
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a plurality of modulators at said headend for generating multiple carrier signals; a plurality of frame synchronizers at said headend for modulating each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; a timing reference generator at said headend for generating a common timing reference signal synchronously related to said time coincident synchronization components; a plurality of encoders at said headend for causing each of said channels signals to be encoded in accordance with a common predetermined encoding rule; data insertion circuitry at said headend for combining said common timing reference signal with a selected encoded channel signal; means for distributing said multiple encoded channels signals from said headend to said subscriber sites as a common RF signal; a data receiver at each subscriber site responsive to at least one of said channel signals for recovering said common timing reference signal; and a single broadband apparatus at each subscriber site to respond to said recovered common timing reference signal to simultaneously decode all of the channel signals distributed thereto by operating upon said common RF signal in accordance with the inverse of said encoding rule to provide a multichannel signal comprising multiple decoded channel signals suitable for direct simultaneous application to a conventional television receiver. - View Dependent Claims (23, 27)
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24. Apparatus for distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, the apparatus comprising:
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a plurality of modulators at said headend for generating multiple carrier signals; a plurality of frame synchronizers at said headend for modulating each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; a timing reference generator at said headend for generating a common timing reference signal synchronous with said time coincident synchronization components; a plurality of encoders at said headend for causing each of said channels signals to be encrypted in accordance with a common predetermined encoding rule; a data modulator at said headend to data modulate a selected encoded channel signal in response to said common timing reference signal; means for distributing said multiple encrypted channels signals from said headend to said subscriber sites as a common RF signal; an interdiction apparatus at each subscriber site for periodically inserting a jamming signal into said common RF signal to generate an interdicted RF signal; a timing recovery circuit at each subscriber site responsive to said common timing reference signal for generating a sync signal; and a single decoder responsive to said sync signal and said interdicted RF signal to simultaneously decrypt said interdicted signal in accordance with the inverse of said encoding rule to generate a recovered multichannel signal comprising multiple decrypted channel signals capable of directly causing a conventional television receiver to produce an intelligible image and at least one scrambled channel signal incapable of directly causing said television receiver to produce an intelligible image.
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25. Apparatus for distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, the apparatus comprising:
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a plurality of modulators at said headend for generating multiple carrier signals; a plurality of frame synchronizers at said headend for modulating each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; a timing reference generator at said headend for generating a common timing reference signal synchronously related to said time coincident synchronization components; a plurality of encoders at said headend for causing each of said channels signals to be encoded in accordance with a common predetermined encoding rule; data insertion circuitry at said headend for combining said common timing reference signal with a selected encoded channel signal; means for distributing said multiple encoded channels signals from said headend to said subscriber sites as a common RF signal; an interdiction apparatus at each subscriber site for periodically inserting a jamming signal into said common RF signal to provide an interdicted RF signal; a data receiver at each subscriber site responsive to at least one of said channel signals for recovering said common timing reference signal; and a single broadband apparatus responsive to said recovered common timing reference signal and said interdicted RF signal to simultaneously decode said interdicted RF signal in accordance with the inverse of said encoding rule to provide a multichannel signal comprising multiple decoded channel signals each capable of directly causing a conventional television receiver to produce an intelligible image and at least one scrambled channel signal incapable of directly causing said television receiver to produce an intelligible image. - View Dependent Claims (26)
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28. Subscriber site apparatus useful in a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band synchronously related to said synchronization components, and wherein each of said channel signals is encoded in accordance with a common encoding rule, said subscriber site apparatus comprising:
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a data receiver responsive to at least one of said channel signals for recovering said common timing reference signal; a single broadband apparatus operable over said RF band and responsive to said recovered common timing reference signal for simultaneously decoding all of said channel signals in accordance with the inverse of said encoding rule to provide multiple decoded channel signals, each capable of directly causing a conventional television receiver to produce an intelligible image; and an interdiction apparatus for periodically inserting a jamming signal into at least one of said multiple decoded channel signals to render it incapable of directly causing said television receiver to produce an intelligible image. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35)
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36. In a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band synchronously related to said synchronization components, and wherein each of said channel signals is encoded in accordance with a common encoding rule, a method for periodically inserting a jamming signal into at least one of said channel signals at a subscriber site to render it incapable of directly causing a television receiver to produce an intelligible image, said method comprising the steps of:
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simultaneously decoding said multiple encoded channel signals using said common timing reference signal to form multiple decoded channel signals; determining an interfering frequency for a selected channel signal; commanding a frequency generator to generate an output of said interfering frequency; and combining said output of said frequency generator with said multiple decoded channel signals.
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37. Subscriber site apparatus useful in a system for distributing from a system headend 1) multiple channel signals defining an RF band, each channel signal having respective video synchronization components in time coincidence and 2) a common timing reference signal within said band synchronously related to said synchronization components, and wherein each of said channel signals is encoded in accordance with a common encoding rule, said subscriber site apparatus comprising:
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an interdiction apparatus for periodically inserting a jamming signal into said RF band to provide an interdicted RF signal; a data receiver responsive to at least one of said channel signals for recovering said common timing reference signal; and a single broadband apparatus operable over said RF band and responsive to said recovered common timing reference signal and said interdicted RF signal to simultaneously decode multiple channel signals in accordance with the inverse of said encoding rule to provide a multichannel signal comprising multiple decoded channel signals capable of directly causing a conventional television receiver to produce an intelligible image and at least one scrambled channel signal incapable of directly causing said television receiver to produce an intelligible image.
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38. A method of distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, said method comprising the steps of:
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generating at said headend multiple carrier signals; modulating at said headend each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; generating a common timing reference signal synchronously related to said time coincident synchronization components; causing each of said channel signals to be encoded at said headend in accordance with a common predetermined encoding rule; modulating a selected encoded channel signal in response to said common timing reference signal; distributing said multiple encoded channel signals from said headend to said subscriber sites as a common RF signal; responding at each subscriber site to said common RF signal to recover said common timing reference signal to simultaneously decode all of the channel signals distributed thereto by operating upon said common RF signal with a single decoder in accordance with the inverse of said encoding rule to provide multiple decoded channel signals, each capable of directly causing a conventional television receiver to produce an intelligible image; and periodically inserting at each subscriber site a jamming signal into at least one of said multiple decoded channel signals to render it incapable of directly causing said television receiver to produce an intelligible image.
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39. A method of distributing multiple video signals, each produced by a different video source at a system headend and each containing picture and synchronization components, to a plurality of subscriber sites located remote from said headend, said method comprising the steps of:
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generating at said headend multiple carrier signals; modulating at said headend each of said carrier signals with a different one of said video signals to form multiple channel signals, all of said channel signals having their respective video signal synchronization components in time coincidence; generating a common timing reference signal synchronously related to said time coincident synchronization components; causing each of said channel signals to be encoded at said headend in accordance with a common predetermined encoding rule; modulating a selected encoded channel signal in response to said common timing reference signal; distributing said multiple encoded channel signals from said headend to said subscriber sites as a common RF signal; periodically inserting a jamming signal at each subscriber site corresponding to at least one encoded channel signal into said common RF signal to provide an interdicted RF signal; and responding at each subscriber site to said common RF signal to recover said common timing reference signal and said interdicted RF signal to simultaneously decode multiple channel signals distributed thereto with a single decoder in accordance with the inverse of said encoding rule to provide multiple decoded channel signals each capable of directly causing a conventional television receiver to produce an intelligible image and at least one scrambled channel signal incapable of directly causing said television receiver to produce an intelligible image.
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Specification