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CABLE TELEVISION MONITORING SYSTEM

  • US 3,769,579 A
  • Filed: 03/31/1972
  • Issued: 10/30/1973
  • Est. Priority Date: 03/31/1972
  • Status: Expired due to Term
First Claim
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1. A method of interrogating a plurality of TV receivers connected to a common program distribution system, with each receiver having a transponder for signaling a common location, including the steps of:

  • sending a start signal to a plurality of transponders over the distribution system, with the start signal providing no interruption to the TV programming and being unique in character, sending a series of clock signals during subsequent vertical blanking intervals of the TV signal, groups of transponders replying to the start signal between subsequent vertical blanking intervals as determined by the number of clock signals received by the individual transponders.

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