×

Transmitter-receiver for non-contact IC card system

  • US 5,866,891 A
  • Filed: 01/11/1996
  • Issued: 02/02/1999
  • Est. Priority Date: 01/11/1995
  • Status: Expired due to Term
First Claim
Patent Images

1. A transmitter-receiver used for an interrogator in a non-contact IC card system which transmits and receives signals between the interrogator and a transponder said transmitter-receiver comprising:

  • a carrier wave oscillating means capable of sweeping an oscillation frequency;

    a resonant wave detecting means for detecting a single resonant frequency of the transponder among carrier waves generated by the carrier wave oscillating means;

    a carrier frequency holding means for maintaining the oscillation frequency of the carrier wave oscillating means at said single resonant frequency detected by the resonant wave detecting means; and

    means for transmitting data between the interrogator and the transponder at said single resonant frequency.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×