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Carrier aided code tracking loop

  • US 5,003,552 A
  • Filed: 11/20/1989
  • Issued: 03/26/1991
  • Est. Priority Date: 11/20/1989
  • Status: Expired due to Term
First Claim
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1. A fast acquisition coherent code tracking loop of the type employed to produce a synchronized PN clock from a received PN code signal, comprising:

  • a PN generator for generating a PN replica code,a code alignment detector coupled to receive said received PN code signal and coupled to said PN generator for providing an unfiltered error signal indicative of the phase offset between the received PN code signal and said PN replica code,a loop filter coupled to receive said unfiltered error signal for producing a phase offset error signal,frequency offset loop means,an accurate VCO having its input port coupled to receive said phase offset error signal and its output port coupled in series with said frequency offset loop means and to said PN generator,a coherent carrier tracking loop for producing an I.F. carrier frequency signal, andscaling means in said coherent carrier tracking loop for injecting scaled carrier tracking loop correction information into said frequency offset loop means to enhance the speed of acquisition of said received PN code signal.

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