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Method and apparatus for estimating local oscillator frequency for GPS receivers

  • US 7,747,236 B1
  • Filed: 12/11/2001
  • Issued: 06/29/2010
  • Est. Priority Date: 12/11/2000
  • Status: Expired due to Fees
First Claim
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1. An apparatus for estimating frequency errors in a local oscillator signal used in GPS receivers, comprising:

  • a local oscillator for generating the local oscillator signal and a sampling clock signal, wherein the sampling clock signal is derived from the local oscillator signal;

    a sampling block coupled to the local oscillator, that receives an external reference signal with a known reference frequency and the sampling clock signal, and generates digital samples of the external reference signal; and

    a local oscillator frequency error estimator module, that determines a frequency error in the local oscillator signal by comparing respective frequencies of the digital samples of the external reference signal and the sampling clock signal.

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