A SYSTEM AND METHOD FOR THE NON-CONTACT TRANSMISSION OF DATA

摘要

A data transmission system for the non-contact transmission of data between a station and a portable data carrier. The station includes a station transmitter operating at a predetermined frequency for generating a first signal and a demodulator for detecting a second signal superimposed on the first signal. An antenna is coupled via a length of cable to the station transmitter via a matching circuit so as to be operative at said frequency regardless of the length of the cable. The portable data carrier includes supply means for coupling to a source of electric power and a data carrier tuned antenna circuit inductively coupled with the station transmitter so as to receive power from the station. A data carrier data modulator is provided for modulating the first signal with the second signal in response to data stored within the data carrier and, by means of said inductive coupling, enabling the data to be transmitted from the data carrier to the station.