公开(公告)号：FR2792132A1

公开(公告)日：2000-10-13

申请号：FR9904544

申请日：1999-04-07

Applicant: ST MICROELECTRONICS SA

Inventor： WUIDART LUC ,  BARDOUILLET MICHEL ,  ENGUENT JEAN PIERRE

IPC: G06K19/07 ,  G06K7/00 ,  G06K17/00 ,  H02J17/00 ,  H04B1/59 ,  H04B5/02 ,  H04B7/14

Abstract: The terminal (1) uses inductive coupling to read from and write to a transponder, and includes a resonant circuit (Li,Ci) tuned to receive an AC HF excitation voltage. The resonant frequency may be altered so as to detune the LC in the event that a transponder is very close to the terminal. A capacitor (24) may be controlled by a control circuit (21) and with impedance (Li) to detect a gap of phase in relation to the signal of REF reference and to modify the capacity Ci of the capacitor (24). An Independent claim is included for a contactless system of data transmission.