Non-contact IC card including antenna circuit with adjustable re

Details Non-contact IC card including antenna circuit with adjustable re Non-contact IC card including antenna circuit with adjustable re

1995-10-04

1997-12-16

Hajec, Donald T.

Registers

Records

Conductive

235439, 34082534, 34082554, G06K 1906

Patent

active

056988389

ABSTRACT:
A non-contact type IC card system has a batteryless non-contact type IC card using an electromagnetic wave as a communication medium and a reading and writing (R/W) unit. To eliminate a problem that the level of a received signal varies depending upon the communication distance between the card and the R/W unit, a comparator detects the received signal level of an antenna resonance circuit for data transmission and reception, before a variable resistance device alters the quality factor Q of the antenna resonance circuit, which results in adjusting the level of the received signal.

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