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Near Field Communication Apparatus

  • US 20140194055A1
  • Filed: 01/04/2013
  • Published: 07/10/2014
  • Est. Priority Date: 01/04/2013
  • Status: Active Grant
First Claim
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1. A system for use in a near field communications (NFC) reader for detecting the presence of an NFC tag, the NFC reader having an antenna tuned to a resonant frequency, the system comprising:

  • a first signal generator for generating a carrier signal whose frequency varies about the resonant frequency;

    a second signal generator for generating a modulating signal for modulating the carrier signal;

    a modulator for modulating the carrier signal with the modulating signal;

    a driver for driving the antenna with the modulated signal; and

    a detection system for detecting harmonics of the modulating signal in a signal present in the antenna as a result of the modulated signal;

    wherein the detection system is configured to generate an output when a third or higher order harmonic is detected.

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