NONCONTACT IC CARD SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an IC card system consisting of a battery-less noncontact IC card and a read-write device, that the position and size of sensitive range between the IC card and the read-write device at the time of read and write to be made same. SOLUTION: The difference of sensitive range is caused by the intensity of carrier power. Thereupon, in order to make same the position and size of sensitive range between the IC card and the read-write device, the intensity of carrier power is varied at the time of read and write. The intensity of carrier power is defined by for example the modulation factor.