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System for securely providing restricted video information

  • US 5,142,576 A
  • Filed: 05/06/1991
  • Issued: 08/25/1992
  • Est. Priority Date: 02/07/1989
  • Status: Expired due to Term
First Claim
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1. A system for securely providing to subscribers restricted signals containing display information, for display on electronic screens, said system including an encoder for encoding update data for updating said display information, and a plurality of decoders for decoding said update data and generating a display of a portion of said display information, characterized in that said encoder comprises:

  • means for generating a first data stream, said first data stream including a plurality of information identification codes each corresponding to a particular portion of said display information, and a plurality of display identification codes each corresponding to one of said plurality of decoders, each of said information identification codes being associated with at least one display identification code to thereby form information identification code-display identification code sets indicative of the particular portion of display information which each subscriber is authorized to receive;

    means for generating a sequence of second data streams including at least one of (i) said information identification codes, (ii) display screen coordinates of an area in a relevant display screen of the respective display information requiring update data, said area having a length less than a full row of data extending across an entire display screen, and (iii) the respective update data; and

    means for transmitting said first data stream followed by said sequence of second data streams;

    and in that each of said decoders comprises;

    means for associating the relevant decoder with one of said display identification codes;

    means for recognizing said one display identification code and for storing the information identification code associated with said one display identification code;

    means for retrieving said display screen coordinates of the update data corresponding to each of said stored information identification codes;

    means for storing said update data at the related display screen coordinates for each associated portion of said display information for subsequent display; and

    means for selectively displaying said stored portion of display information.

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