| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a back scatter system into which QPSK modulation processing is introduced. <P>SOLUTION: The system is provided with a first signal path for acquiring a first reflection wave obtained by directly reflecting a reception radio wave without allowing the radio wave to pass through any phase shifter, a second signal path for acquiring a second reflection wave which reciprocates through only the first phase shifter and has a phase shifted by π/2 compared with the first reflection wave, a third signal path for acquiring a third reflection wave which reciprocates through the first phase shifter and a second phase shifter and has a phase shifted by π compared with the first reflection wave, and a fourth signal path for acquiring a fourth reflection wave which reciprocates through the first-third phase shifters and has a phase shifted by 3π/2 compared with the first reflection wave. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
