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US 4,688,247 AGranted
Pay TV scrambling by audio encryption
AssigneeOak Industries Inc.
InventorMircho A. Davidov
Life of this patent
Estimating the term…
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AssigneeOak Industries Inc.
InventorMircho A. Davidov
Estimating the term…
A subscription television distribution system provides a plurality of sources of television program channels, each of which include a video signal and an encrypted audio signal with the encrypted audio signal including encrypted control and subscriber address data. There is a communication link connecting the plurality of sources with at least one receiving site such as a cable system head end which has means for receiving the plurality of television channels. At the receiving site, the encrypted audio signals are separated from the television channel and are multiplexed together on an non-television channel carrier. An identifying tag is added to each of the video signals for use in subsequently selecting the audio signal corresponding to its associated video signal when the encrypted audio signals are demultiplexed at subscriber locations. At each subscriber there is a TV audio decrypter which selects the tag from a video signal and uses that tag to demultiplex a particular audio signal. The audio signal is then decrypted and is combined with the video signal to provide program information for the subscriber.
In a subscription TV distribution system, a plurality of sources of TV program channels, each including a video signal and an encrypted audio signal, with the encrypted audio signal including encrypted control and subscriber address data,
A TV audio decrypter for use with a TV subscription distribution system in which a plurality of encrypted audio signals are multiplexed together on a non-TV channel carrier and in which the corresponding plurality of video signals are transmitted separately, each with an identifying tag for its associated audio, including
A TV audio decrypter for use with a TV subscription distribution system in which a plurality of encrypted audio signals are multiplexed together on a non-TV channel carrier and in which the corresponding plurality of video signals are transmitted separately, each with an identifying tag for its associated encrypted audio, including:
Dependencies are inferred from the claim text.