Memory select system for an STV decoder
First Claim
1. A subscription television system comprising:
- means for broadcasting a scrambled television signal having encoded in the vertical intervals thereof a p-bit program code and an m-bit memory read code together defining the programming category of said television signal and a p-bit subscriber authorization code and an m-bit memory write code together at least partially defining a subscriber'"'"'s decode authorization status; and
a decoder comprisingmeans for receiving and converting said broadcast television signal to a corresponding baseband video signal;
a memory having (2m) individually addressable p-bit memory locations;
means responsive to said baseband video signal for storing only a single p-bit subscriber authorization code at a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit memory write code;
means responsive to said baseband video signal for developing a decode authorization signal in response to the detection of a predetermined relationship between a received p-bit program code and the contents of a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit memory read code; and
means responsive to said decode authorization signal for unscrambling said baseband video signal.
3 Assignments
0 Petitions
Accused Products
Abstract
A subscription television system includes means broadcasting a scrambled television signal encoded with p-bit program and subscriber authorization codes and m-bit memory write and read codes. Each subscriber is provided with a decoder having (2m) p-bit memory locations, the decoder being operable for storing a broadcast p-bit subscriber authorization code in a memory location defined by the broadcast m-bit memory write code for updating the decode authorization status of the subscriber and being operable for comparing a broadcast program code with a subscriber authorization code stored in a memory location defined by the broadcast m-bit memory read code for developing a decode authorization signal to effect unscrambling of the broadcast television signal.
125 Citations
11 Claims
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1. A subscription television system comprising:
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means for broadcasting a scrambled television signal having encoded in the vertical intervals thereof a p-bit program code and an m-bit memory read code together defining the programming category of said television signal and a p-bit subscriber authorization code and an m-bit memory write code together at least partially defining a subscriber'"'"'s decode authorization status; and a decoder comprising means for receiving and converting said broadcast television signal to a corresponding baseband video signal; a memory having (2m) individually addressable p-bit memory locations; means responsive to said baseband video signal for storing only a single p-bit subscriber authorization code at a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit memory write code; means responsive to said baseband video signal for developing a decode authorization signal in response to the detection of a predetermined relationship between a received p-bit program code and the contents of a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit memory read code; and means responsive to said decode authorization signal for unscrambling said baseband video signal. - View Dependent Claims (2, 3)
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4. A subscription television system comprising:
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means for broadcasing a scrambled television signal having encoded in a selected vertical interval thereof (a) a p-bit program code and an m-bit memory read code together defining the programming category of said television signal; (b) a plurality of subscriber address codes each uniquely identifying a different system subscriber; (c) an m-bit memory write code; (d) a plurality of p-bit subscriber authorization codes each associated with a respective one of said subscriber address codes and at least partially defining together with said m-bit memory write code the decode authorization status of the system subscriber identified by the associated subscriber address code; and a plurality of decoders each corresponding to a respective one of said subscriber address codes and each comprising (a) means for receiving and converting said broadcast television signal to a corresponding baseband video signal; (b) a memory having (2m) individually addressable p-bit memory locations; (c) means responsive to said baseband video signal for storing only the single p-bit subscriber authorization code associated with a subscriber address code identifying a respective one of said decoders at a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit write code; (d) means responsive to said baseband video signal for developing a decode authorization signal in response to the detection of a predetermined relationship between said program code and the contents of a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit read code; and (e) means responsive to said decode authorization signal for unscrambling said baseband video signal.
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5. In a subscription television system having a plurality of decoders each including a memory having a plurality of individually addressable p-bit memory locations each adapted for storing a p-bit subscriber authorization code for comparison with a broadcast p-bit program code to determine the decode authorization status of the decoder, the improvement comprising:
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means for broadcasting a selected memory write code and a selected memory read code; means for updating the memory of said decoder by storing only a single broadcast p-bit subscriber authorization code in a selected p-bit memory location of said memory addressed by said broadcast memory write code; and means for determining the decode authorization status of said decoder by comparing the broadcast p-bit program code with a selected p-bit subscriber authorization code stored in the p-bit memory location of said memory addressed by by said broadcast memory read code.
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6. A decoder for use in a subscription television system having means for broadcasting a scrambled television signal including encoded in the vertical intervals thereof a p-bit program code and an m-bit memory read code together defining the programming category of said television signal and a p-bit subscriber authorization code and an m-bit memory write code together at least partially defining a subscriber'"'"'s decode authorization status, said decoder comprising:
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means for receiving and converting said broadcast television signal to a corresponding baseband video signal; a memory having (2m) individually addressable p-bit memory locations; means responsive to said baseband video signal for storing only a single p-bit subscriber authorization code at a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit memory write code; means responsive to said baseband video signal for developing a decode authorization signal in response to the detection of a predetermined relationship between said program code and the contents of a selected memory location of said memory whose address is determined in accordance with said m-bit memory read code; and means responsive to said decode authorization signal for unscrambling said baseband video signal. - View Dependent Claims (7, 8)
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9. A decoder for use in a subscription television system having means for broadcasing a scrambled television signal including encoded in a selected vertical interval thereof
(a) a p-bit program code and an m-bit memory read code together defining the programming category of said television signal; -
(b) a plurality of subscriber address codes each uniquely identifying a different system decoder; (c) an m-bit memory write code; (d) a plurality of p-bit subscriber authorization codes each associated with a respective one of said subscriber address codes and at least partially defining together with said m-bit memory write code the decode authorization status of the system decoder identified by the associated subscriber address code, said decoder comprising; (a) means for receiving and converting said broadcast television signal to a corresponding baseband video signal; (b) a memory having (2m) individually addressable p-bit memory locations; (c) means responsive to said baseband video signal for storing only the single p-bit subscriber authorization code associated with each subscriber address code identifying a respective one of said decoders at a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit write code; (d) means responsive to said baseband video signal for developing a decode authorization signal in response to the detection of a predetermined relationship between said program code and the contents of a selected p-bit memory location of said memory whose address is determined in accordance with said m-bit read code; and (e) means responsive to said decode authorization signal for unscrambling said baseband video signal.
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10. In a subscription television system including means for broadcasting a selected memory write code and a selected memory read code and having a decoder including a memory having a plurality of individually addressable p-bit memory locations each adapted for storing a p-bit subscriber authorization code for comparison with a p-bit broadcast program code to determine the decode authorization status thereof, the improvement in said decoder comprising:
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means for updating the memory of said decoder by storing only a single broadcast p-bit subscriber authorization code in a selected p-bit memory location of said memory addressed by said broadcast memory write code; and means for determining the decode authorization status of said decoder by comparing the broadcast p-bit program code with a selected p-bit subscriber authorization code stored in the p-bit memory location of said memory addressed by said broadcast memory read code.
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11. In a subscription television system having a plurality of decoders each including a memory having a plurality of individually addressable p-bit memory locations each adapted for storing a p-bit subscriber authorization code for comparison with a broadcast p-bit program code to determine the decode authorization status of a subscriber, the improvement comprising:
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broadcasting a selected memory write code and a selected memory read code; updating said memory by storing only a single broadcast p-bit subscriber authorization code in a selected p-bit memory location of said memory addressed by said memory write code; and determining the decode authorization status of a subscriber by comparing the broadcast p-bit program code with a selected p-bit subscriber authorization code stored in a p-bit memory location of said memory addressed by said memory read code.
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Specification