| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a reader/writer device for a wireless tag excellent in reception sensitivity without being influenced by leakage noises including reflection noises due to an impedance mismatching loss. <P>SOLUTION: In the device, a level detection unit 8 detects leakage noises S444 including reflection noises caused by transmission of a first transmission signal S31 from an antenna 6, a control unit 15 calculates a control voltage S21 and a control voltage S22, a phase shift unit 10 adjusts the phase of a second local oscillation signal S83 according to the control voltage S22, an attenuation unit 9 adjusts the output of the signal S83 according to the control voltage S21, a mixing unit 7 combines the output of the signal S83 with a reception signal S42 to remove the noises S444 including the reflection noises. <P>COPYRIGHT: (C)2010,JPO&INPIT |
