| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a radio tag communication system capable of sufficiently eliminating a sneak path signal from a sender side with a reception section of a simple configuration. <P>SOLUTION: The radio tag communication system includes: an array antenna 58 for receiving a return signal; a cancel signal generating section 60 for generating a cancel signal to eliminate a sneak pass signal generated in the array antenna 58 resulting from a transmission signal; a cancel signal control section 54 for controlling the phase and/or the amplitude of the cancel signal generated from the cancel signal generating section 60; and a received signal composition section 32 for compositing received signals received by each of a plurality of transmission/reception antenna elements 20. The communication apparatus carries out the transmission processing of the transmission signal and the reception processing of the return signal at the same time, and gives the cancel signal outputted from the cancel signal generating section 60 to the received signal composite section 32 which combines the cancel signal with the received signal. Thus, the signal to a noise ratio of a detection output in the case of demodulating the composite signal is enhanced so that a communication distance can be extended. <P>COPYRIGHT: (C)2007,JPO&INPIT |
