| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an IC tag with a simple structure capable of easily specifying a distance, and to provide an article management system, an entrance/exit management system and a tracking system using it. <P>SOLUTION: In this IC tag 10, a reception circuit 13 demodulates a reception signal received by an antenna 11, inputs it to a CPU 15, and inputs it to a level detection circuit 17. The level detection circuit 17 outputs a voltage level of the inputted reception signal to the CPU 15. The CPU 15 A/D-converts an inputted analog signal to detect electric wave intensity. The CPU 15 reads identification information for uniquely identifying itself from a memory 16. The CPU 15 transmits read data from the antenna 11 through a transmission circuit 14 with detected electric wave intensity data and the read identification information included in the read data. A reader/writer 20 detects a communication state (the electric wave intensity, the distance or the like) in each the IC tag 10 on the basis of the received identification information and electric wave intensity data from the IC tag 10. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
