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Wireless communication system

  • US 7,408,456 B2
  • Filed: 09/06/2002
  • Issued: 08/05/2008
  • Est. Priority Date: 09/13/2001
  • Status: Expired due to Fees
First Claim
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1. A communications system comprising:

  • a transmitter arranged to transmit bursts of RF energy at a regular period;

    a communication unit having an antenna through which RF energy is received from the transmitter, a control element having one or more states, and an electrical circuit for generating, controlling the period of, and transmitting a pulsed RF output signal from the communications unit in dependence on the state of the control element, through a second antenna; and

    a receiving communications unit having a receiver for receiving the pulsed RF signal from the communications unit, and including an electrical circuit for detecting, as a parameter of the pulsed RF signal, the time of receipt of the pulsed RF output signal, determining if a change in the period of receipt of the responses occurs and, if so, generating an output control signal dependent on the change in the period of receipt of the pulsed RF signal.

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