| 摘要 |
<p>PURPOSE:To send individual data to an interrogator without crosstalk even when plural IC cards are in existence for a prescribed time in a same radio wave coverage area in the vicinity of the interrogator. CONSTITUTION:An IC card device 2 approaches an interrogator 1, the energy of a radio wave received by a reception circuit 11 is increased. When a reception level decision circuit 12 decides it that the energy of the radio wave exceeds a preset threshold level, individual data stored in a memory 15 are extracted and sent repetitively by a transmission circuit 13. When the count of a counter 14 reaches a preset count, the counter 14 stops the transmission. A timer 16 allows a reception circuit 11 to stop the reception of a frequency sent by the transmission circuit 3 in the interrogator 1 for a prescribed time when the reception level decision circuit 12 decides it that the energy of the radio wave received by the reception circuit 11 exceeds a preset threshold level.</p> |
