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Controller for coded surface acoustical wave (SAW) security system

  • US 4,931,664 A
  • Filed: 08/02/1988
  • Issued: 06/05/1990
  • Est. Priority Date: 08/02/1988
  • Status: Expired due to Fees
First Claim
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1. A motor vehicle access system comprising:

  • (a) signal generating means for generating an uncoded signal;

    (b) coupling means operatively connected to said signal generating means for converting said uncoded signal to an uncoded electromagnetic signal;

    (c) a surface acoustical wave (SAW) device operatively connected to said coupling means for receiving said uncoded electromagnetic signal therefrom, converting said uncoded electromagnetic signal to a coded surface acoustic wave and transferring said coded surface acoustic wave to said coupling means for generating a coded electromagnetic reply signal;

    (d) amplifying means operatively connected to said coupling means for amplifying said coded electromagnetic reply signal;

    (e) comparing means operatively connected to said amplifying means for comparing said coded reply signal to a previously stored code; and

    (f) enabling means operatively connected to said comparing means for enabling operation of a motor vehicle when said code and said coded reply signal are successfully compared.

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