| 摘要 |
A local wireless communications system for accurately grasping a channel in which interference is generated is provided to recognize the channel in which interference is generated and improve the recognition distance of RF signal, receive sensitivity and recognition rate due to control the channel operation of a reader. A first oscillation circuit(160) produces a first oscillation signal. A second oscillation circuit(165) produces a first oscillation signal. A controller(145) controls the first oscillation circuit and the second oscillation circuit. A first mixer unit(110) mixes the first oscillation signal and a received signal and converts into the first intermediate frequency signal. A second mixer part(175) converts into the first intermediate frequency signal and the second intermediate frequency signal of the same band. A third mixer part(130) mixes the first intermediate frequency signal and the second intermediate frequency signal and extracts a tag signal.
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