High security pay television system
First Claim
1. A pay television broadcast system comprisinga broadcast station including scrambling means for imposing a scrambling signal on the program signal, the scrambling signal being generated through use of the inverse of a signal generated from a pre-selected changeable system code, the broadcast station also broadcasting a broadcast code with the broadcast signal, the broadcast code identifying the program being broadcast;
- a plurality of receiving station decoders each including descrambling means for imposing a descrambling signal complementary to the scrambling signal on the received broadcast signal, the descrambling signal being generated from the same system code, each receiving station decoder including therein a fixed, station-unique internal code, the receiving station decoder further including means for demodulating the broadcast signal to recover the broadcast code;
a removable, transportable digital memory module for each receiving station decoder, each module carrying thereon a fixed, station-unique external code which can be combined with the internal code of the proper receiving station to generate the system code in the receiving station, the module also having a portion onto which information as to programs descrambled by the decoder may be written, the memory module being periodically removed from the receiving station and replaced with a new memory module so that the system code can be periodically changed;
1 Assignment
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Accused Products
Abstract
A high security pay television system is provided in which subscribers are provided with a decoder and with periodically changed removable memory modules. The decoder only functions to properly descramble the scrambled broadcast signal when a changeable system-wide code is available in the decoder. The code can either be carried in the memory module, or an internal code unique to the decoder and resident in the decoder can be combined with an external code in the removable memory module, and also unique to that decoder, to generate the common systemwide system code. Program viewership is written on the removable memory module which is returned to a central facility for later subscriber billing.
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Citations
24 Claims
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1. A pay television broadcast system comprising
a broadcast station including scrambling means for imposing a scrambling signal on the program signal, the scrambling signal being generated through use of the inverse of a signal generated from a pre-selected changeable system code, the broadcast station also broadcasting a broadcast code with the broadcast signal, the broadcast code identifying the program being broadcast; -
a plurality of receiving station decoders each including descrambling means for imposing a descrambling signal complementary to the scrambling signal on the received broadcast signal, the descrambling signal being generated from the same system code, each receiving station decoder including therein a fixed, station-unique internal code, the receiving station decoder further including means for demodulating the broadcast signal to recover the broadcast code; a removable, transportable digital memory module for each receiving station decoder, each module carrying thereon a fixed, station-unique external code which can be combined with the internal code of the proper receiving station to generate the system code in the receiving station, the module also having a portion onto which information as to programs descrambled by the decoder may be written, the memory module being periodically removed from the receiving station and replaced with a new memory module so that the system code can be periodically changed; - View Dependent Claims (3, 4, 7, 8, 9, 11, 13, 15, 16, 17, 18, 19, 20, 22, 23, 24)
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2. the receiving station decoder also having means for writing on the memory module program information derived from the broadcast code indicating the programs actually descrambled;
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means at a remote location, to which replaced memory modules are transported, for reading the memory modules to generate viewing usage charges based on the programs actually descrambled. - View Dependent Claims (5, 6)
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10. In a pay television system, a receiving station signal decoder for a scrambled broadcast signal comprising
an internal fixed memory containing a fixed, station-unique internal code; -
a removable, electrically alterable, removable memory module containing at least one pre-written station-unique, external code which can be combined with the internal code to generate a systemwide system code, and also a portion onto which program information may be entered; means for generating a descrambling signal complementary to the scrambling signal upon input of a proper numerical sequence; and a microprocessor programmed (1) to read the internal code from the fixed memory and the external code from the portable memory module, (2) to combine the external code with the internal code to generate the systemwide system code, to generate and output to the descrambling signal generating means a numerical signal generated from the system code, (4) to derive a broadcast code from the scrambled broadcast signal, and (5) to write information about programs actually descrambled, as determined from the broadcast code, in the memory module so that use of the decoder can be billed on a usage basis. - View Dependent Claims (12, 14)
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21. A pay television broadcast system comprising
a broadcast station including (1) scrambling means for imposing a scrambling signal on the program signal to create a scrambled broadcast signal, the scrambling signal being the inverse of a signal generated from a pre-selected changeable code, and (2) an encoder to imbed a broadcast code in the broadcast signal; -
a portable, removable reusable memory module for each viewing station changeable code thereon; a receiving station carrying the decoder for each receiving station including (1) means for reading the changeable code from a removable memory module inserted in the decoder, (2) means for imposing a descrambling signal complementary to the scrambling signal on the received broadcast signal, the descrambling signal being generated from the hangeable code, and (3) writing means for writing at least a portion of the broadcast code in the memory module so that the memory module can later be read at a remote location to determine the broadcast segment viewed at the receiving station; and a central billing location to which memory modules are sent including means to read the information written in the memory modules to create viewer charge information base on the actual programs descramble.
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Specification