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Demodulator for contactless chip card

  • US 6,031,419 A
  • Filed: 09/18/1998
  • Issued: 02/29/2000
  • Est. Priority Date: 09/23/1997
  • Status: Expired due to Term
First Claim
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1. A demodulator of binary data for a contactless chip card with transmission by radio frequency signals, said demodulator comprising:

  • a detector for receiving a radio frequency signal and generating a detected signal responsive thereto;

    a rectifier for generating a rectified signal based upon the detected signal;

    a bandpass filter for generating a first signal at low frequency and a second signal at high frequency based upon the rectified signal;

    a comparator stage for comparing the first and second signals; and

    a memory for storing a result of a comparing by said comparator stage.

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