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Automatic frequency control system

  • US 5,155,466 A
  • Filed: 06/20/1991
  • Issued: 10/13/1992
  • Est. Priority Date: 06/22/1990
  • Status: Expired due to Term
First Claim
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1. An automatic frequency control system comprising:

  • a resonance transmitting unit for transmitting a center frequency of a transmission data inputted through alternate current power lines;

    a carrier transmitting unit for converting said transmission data of said resonance transmitting unit into digital signals and transmitting the converted digital signal to a data line of a microcomputer;

    a frequency detecting unit for shaping and outputting the transmission frequency of said resonance transmitting unit;

    a highest limit oscillation unit for generating a highest limit frequency;

    lowest limit oscillation unit for generating a lowest limit frequency;

    a comparing unit for comparing the transmission frequency outputted from said frequency detecting unit with said highest and lowest limit frequencies of said highest and lowest limit oscillation units, respectively, and applying the compared resultant signal to said microcomputer; and

    a resistance varying unit for varying the resistance according to a resistance setting control signal generated from said microcomputer so as to automatically set the frequency at the transmission frequency of said carrier transmitting unit.

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