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Process for the broadcasting of programmes with progressive conditional access and separation of the information flow and the corresponding receiver

  • US 5,742,681 A
  • Filed: 04/04/1995
  • Issued: 04/21/1998
  • Est. Priority Date: 04/06/1994
  • Status: Expired due to Term
First Claim
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1. A method for broadcasting programs with progressive conditional access, comprising the steps of:

  • breaking an information flow of a program into a first flow and a second flow, said breaking step comprising,arranging said first flow into a channel of order i in groups of m successive fixed length frames, said fixed length frames comprising variable length channels arranged in plural orders,arranging said second flow into the channel of order i in groups of p successive fixed length frames;

    scrambling the second flow with a control word; and

    transmitting an entitlement checking message with said program so that a receiver equipped with an access right may descramble and restore the information flow, reception of the first flow resulting in a partially discernable program and reception of said second flow, once descrambled, resulting in complete restoration of the program, said transmitting step comprising the steps of,transmitting said program in said channel of order i, andmultiplexing said groups of m successive fixed length frames alternately with said groups of p successive fixed length frames.

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