| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve read-out accuracy of an RFID reader. Ž<P>SOLUTION: A noise suppressor 27 for an RFID reader 4 includes: an attenuation circuit 28 for inputting and attenuating a transmission wave; a phase-shift circuit 29 capable of shifting the phase of an output signal from the attenuation circuit 28 by adding a predetermined phase to 0° to 360°; a synthesis circuit 30 for synthesizing a response signal received from an RFID tag 3 and an output from the phase-shift circuit 29; and a control circuit 31 for controlling the attenuation amount of the attenuation circuit 28 to be substantially equal with the amplitude of the output of a leak signal of the output of the attenuation circuit 28 directly received as a leak wave of the transmission wave, and controlling the phase-shift amount of the phase-shift circuit 29 by adding the predetermined phase to 0° to 360° to be substantially equal with the reversed phase of the leak signal. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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