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Mechanism for deriving accurate frequency reference for satellite communications burst demodulator

  • US 4,932,070 A
  • Filed: 08/22/1988
  • Issued: 06/05/1990
  • Est. Priority Date: 08/22/1988
  • Status: Expired due to Term
First Claim
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1. For use with a communication system having a first station and a second station remote with respect to said first station, said first and second stations communicating with one another over a communication link that subjects the carrier frequencies of signals transmitted thereover to an offset of their respective frequencies, said first station modulating information signals for delivery to said second station onto a first carrier frequency that is transmitted by said first station over said link on a continuous basis, said second station modulating information signals for delivery to said first station onto a second carrier frequency that is transmitted over said link on a burst mode basis, a method of enabling information signals, modulated onto said second carrier frequency which is transmitted on a burst mode basis from said second station over said link to said first station and thereby subjected to said frequency offset, to be recovered at said first station comprising the steps of:

  • at said second station,(a) generating said second carrier frequency in accordance with a reference signal derivable from said first carrier frequency received thereby; and

    at said first station,(b) receiving each of said first and second carrier frequencies that have been transmitted over said communication link; and

    (c) deriving, from said first and second carrier frequencies, a filtered burst demodulation reference frequency for demodulating information signals that have been modulated onto said second, burst mode carrier frequency by said second station.

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