| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication system for preventing the mutual interference between interrogators and responders, identifying each of the responders, and having reduced power consumption when a plurality of interrogators and responders are closely arranged, and to provide an interrogator and a responder for the communication system. SOLUTION: The communication system 1 comprises the interrogators 10-12 and the responders 20-25. A main carrier wave FC1 is transmitted from the interrogator 10, and reflected waves f1-f6 are transmitted back from the responders 20-25 respectively. When the plurality of interrogators 10-12 exist comparatively closely, a shared carrier wave and responder signals are detected before transmission. Since another interrogator transmits a shared carrier wave in advance, if the signal of a target responder modulating and reflecting the shared carrier wave can be detected, only the detection is continued, thus unnecessary transmission of shared carrier waves which cause the collision of signal waves can be prevented. Further, since the transmission of carrier waves having large power consumption is not performed, power-saving of each responder can be realized. COPYRIGHT: (C)2004,JPO
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