| 摘要 |
An RFID reader system has an RFID tag and an RFID reader. The tag authorizes the RFID reader by receiving a plurality of successively-transmitted initial RFID read signals and determining respective initial-read signal power levels of the received initial RFID read signals. Using the determined initial-read signal power levels, a controller automatically selects an authorization sequence. A plurality of successively-transmitted authorization RFID signals are received sequentially, and respective authorization-signal power levels of the received authorization RFID read signals are determined. The determined authorization-signal power levels are automatically compared to the authorization sequence using the controller, so that the RFID reader is authorized if the determined authorization-signal power levels correspond to the authorization sequence.
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