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Frequency Reference Compensation

  • US 5,542,095 A
  • Filed: 08/24/1993
  • Issued: 07/30/1996
  • Est. Priority Date: 08/24/1993
  • Status: Expired due to Term
First Claim
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1. A frequency reference compensation system, comprising:

  • a downconverter for mixing a received signal with a local oscillator signal to provide a downconverted signal, the downconverted signal being output from said downconverter;

    a demodulator interfaced with said downconverter for determining a frequency offset between a frequency of said downconverted signal and a predetermined frequency of the downconverted signal, said demodulator providing a frequency control signal representative of said frequency offset;

    an accumulator coupled to said demodulator for accepting each said frequency offset so determined and accumulating values indicative of said frequency offsets;

    a comparator coupled to said accumulator for comparing said accumulated values to a predefined threshold and following a complete reception of said received signal adjusting said frequency control signal to define an adjusted frequency control signal based on said comparison;

    a voltage controlled oscillator interfaced with said comparator for accepting said adjusted frequency control signal and for generating a reference signal having a reference frequency based on said frequency offset; and

    a frequency synthesizer coupled to said voltage controlled oscillator and having an input of said reference signal and generating said local oscillator signal based on said reference frequency thereby adjusting said frequency of said downconverted signal to minimize the frequency offset.

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