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Active RF tag with wake-up circuit to prolong battery life

  • US 6,593,845 B1
  • Filed: 09/29/1999
  • Issued: 07/15/2003
  • Est. Priority Date: 01/09/1998
  • Status: Expired due to Term
First Claim
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1. An active RF transponder including electronic circuitry, comprising:

  • a battery;

    an antenna adapted to receive RF signals from an interrogator;

    an oscillator adapted to provide a clock signal having a duty cycle; and

    a wake-up circuit coupled to the antenna and the oscillator and adapted to periodically sample said RF signals for presence of an interrogation signal, said duty cycle defining the intervals during which the antenna is sampled for presence of the interrogation signal.

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