| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a contactless IC card reader/writer capable of reliably communicating with an IC card even when the impedance of the IC card varies. <P>SOLUTION: If the IC card 3 is brought nearer to the contactless IC card reader/writer in a state that a carrier wave is modulated by a test modulation signal, the amplitude of a transmission signal is affected by the impedance of the IC card 3 and changes. When detecting the IC card (S4: YES), the reader/writer detects the transmission signal (S5) to calculate a modulation factor (S6). At this time, when the modulation factor is within a predetermined range (S7: YES), ordinary communication is performed (S9), and when the modulation factor is beyond the predetermined range (S7: NO), the modulation factor is modified (S8). This enables the IC card 3 to communicate in a state that the modulation factor of the transmission signal is appropriately adjusted. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
