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Non-contact IC card system and non-contact IC card

  • US 6,747,548 B1
  • Filed: 03/21/2000
  • Issued: 06/08/2004
  • Est. Priority Date: 06/18/1997
  • Status: Expired due to Fees
First Claim
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1. A non-contact IC card system comprising:

  • a reader/writer and a non-contact IC card, wherein at least one of said reader/writer and said non-contact IC card includes;

    an AM demodulating circuit for converting a reception signal being a carrier AM-modulated by transmission data into a binary signal by comparing said reception signal with a reference value and further for detecting said transmission data by comparing a pulse width of the converted binary signal with a width of a reference pulse feedbacked to vary in accordance with a variation of said pulse width of the converted binary signal.

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