| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve a problem that a conventional transmission/reception circuit can not reduce an influence of a transmission leak signal. <P>SOLUTION: This transmission/reception circuit carries out transmission of a carrier signal and reception of a tag response signal between an RFID tag and itself at the same time, and includes: an RF front end part 20 for outputting an intermediate signal Sin including a tag response signal RX, a reflection carrier signal TXd arising from a carrier signal TX, and a leakage carrier signal TX1 arising from the carrier signal TX; and an orthogonal demodulator 30 for demodulating the intermediate signal Sin based on an I local signal to output the tag response signal RX and demodulating the intermediate signal Sin based on a Q local signal to output a transmission leak signal including the reflection carrier signal TXd and the leakage carrier signal TX1. The RF front end part 20 makes the phase of the tag response signal included in the intermediate signal Sin substantially identical to the phase of the I local signal, and sets the envelope waveform of the intermediate signal nearly at a constant voltage level. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
