摘要 |
An IC card, an IC card processor, and an IC card system are simply arranged to perform full-duplex data exchange efficiently using a frequency band in such a manner that a transmission signal sent from the IC card processor is received by an antenna, the transmission signal is demodulated, and a response signal to be sent from the antenna is formed by modulating a main carrier having the same frequency as a main carrier of the transmission signal with a response data sequence in such a manner that a sideband of the response signal does not overlap a sideband of the transmission signal along the frequency axis.
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