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Spread spectrum communication apparatus and demodulator surface acoustic wave element and surface acoustic wave parts for spread spectrum communication

  • US 5,909,461 A
  • Filed: 07/10/1996
  • Issued: 06/01/1999
  • Est. Priority Date: 07/10/1995
  • Status: Expired due to Fees
First Claim
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1. A surface acoustic wave element comprising:

  • a piezoelectric substrate;

    a signal input encoding electrode formed on said piezoelectric substrate;

    a first output comb-like electrode formed on said piezoelectric substrate at a location that is spaced apart from said signal input encoding electrode by a predetermined interval anda second output comb-like electrode formed on said piezoelectric substrate at a location that is spaced apart from said first output comb-like electrode by T+(±

    n+a/8)/fc, T being one period of a signal to be received and demodulated, n being an integral number between 0 and a value twice as large as the ratio of a carrier frequency fc of a signal inputted to said signal input encoding to a chip rate which is a frequency corresponding to an interval between comb-like electrode pairs or groups of comb-like electrode pairs of said signal input encoding electrode, said comb-like electrode pairs or groups of electrode pairs corresponding to a code series, and a satisfying 1/2≦

    a≦

    3/2.

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