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Circuit for detecting a shifted frequency, a method for detecting a shifted frequency and portable communication apparatus

  • US 20040091026A1
  • Filed: 10/29/2003
  • Published: 05/13/2004
  • Est. Priority Date: 10/31/2002
  • Status: Active Grant
First Claim
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1. A circuit for detecting a shifted frequency, comprising:

  • a path selection unit for measuring a delay profile of a spread signal that has passed through a plurality of paths, and searching and selecting an optimum path from among said plurality of paths;

    a plurality of finger processing units for reverse spreading the spread signal of each path, which is allocated by said path selection unit, by a spread code replica, obtaining a channel estimated value including at least phase variation component with respect to said path by using a given pilot symbol that is included in the signal after the reverse spread, and carrying out coherent detection by using said channel estimated value;

    a phase difference measuring unit for measuring a phase difference from each phase variation component by each of said finger processing units;

    a path timing difference measuring unit for measuring a periodical path timing difference depending on said delay profile;

    a frequency error detecting unit for detecting a frequency error of said signal by using said path timing difference and said phase difference; and

    a Doppler frequency detecting unit for detecting a Doppler frequency on the basis of said frequency error.

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