| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide, as a method for measuring a distance to an RFID tag, a measurement capable of accommodating to a setting of an actual communication processing. <P>SOLUTION: A communication processing device 1 includes a high frequency signal oscillator 11B and an intermediate frequency oscillator 11A, generates carrier wave in which an intermediate frequency signal is superimposed, using the oscillators 11A and 11B; and transmits it from an antenna 10. Mixers 16i and 16q separate the intermediate frequency signal in signals that the antenna 10 has received, into an I signal and a Q signal and extracts them therefrom. A phase difference detecting section 112 detects, using the I signal and the Q signal after a reception of reflected wave from a tag 2 has started, a phase difference of the intermediate frequency signal in the reflected wave with respect to the intermediate frequency signal in the carrier wave. A distance calculating section 113 calculates a distance from the antenna 10 to the tag 2 using the phase difference and the wavelength of the intermediate frequency signal. <P>COPYRIGHT: (C)2013,JPO&INPIT |
