| 摘要 |
<p>PROBLEM TO BE SOLVED: To build up an inexpensive radio frequency identification(RFID) network having one interrogator or over with a means having an RFID function, a sensor function, and a motion detection and sensor data analysis function. SOLUTION: A radio communication system has interrogators 103, 104 that generate and transmit a radio signal. The radio communication system includes one tag 105 (106, 107) or over. A backscatter modulator uses a sub carrier signal to modulate a reflected radio signal and to form a reflected modulation signal. The interrogator receives and demodulates the reflected modulation signal. Based on the characteristic of the demodulated signal, the interrogator discriminates identification information of the tags 105, 106, 107 and a relative speed of each tag with respect to the interrogator. The interrogator can discriminate whether or not there is a motion around the interrogator independently of the presence of a tag without the need for other motion detection system. Moreover, the characteristic of a tag motion such as a vibration frequency is discriminated based on the characteristic of the demodulation signal.</p> |
