Multi-protocol or multi command RFID system

摘要

A multi-protocol RFID interrogating system employs a synchronization technique (step-lock) for a backscatter RFID system that allows simultaneous operation of closely spaced interrogators. The multi-protocol RFID interrogating system can communicate with backscatter transponders having different output protocols and with active transponders including: Title 21 compliant RFID backscatter transponders; IT2000 RFID backscatter transponders that provide an extended mode capability beyond Title 21; EGO™ RFID backscatter transponders, SEGO™ RFID backscatter transponders; ATA, ISO, ANSI AAR compliant RFID backscatter transponders; and IAG compliant active technology transponders. The system implements a step-lock operation, whereby adjacent interrogators arc synchronized to ensure that all downlinks operate within the same time frame and all uplinks operate within the same time frame, to eliminate downlink on uplink interference.

主权项

1. An interrogator for communication with RFID tags having transmitter components for processing transmit signals representing a plurality of communication protocols along a transmitter path, and receiver components for processing received signals for the plurality of communication protocols along a receiver path, said interrogator comprising:
an encoder generating first and second test signals having bits for the plurality of protocols and transmitting said test signals through each of the transmitter components along the transmitter path and through each of the receiver components along the receiver path; a decoder for receiving said bits of said test signals from a last component in one of the transmitter path or receiver path; and a processor comparing said test signals generated by said encoder with said received bits, and determining that the transmitter and receiver components are operating properly if all of said bits of the test signals generated by said encoder match all of said received bits, wherein said transmitter transmits a first broadcasted signal corresponding to a first communication protocol through an antenna, a second broadcasted signal corresponding to a second communication protocol through said antenna, said first test signal corresponding to said first communication protocol directly to said receiver components, bypassing said antenna; and said second test signal corresponding to said second communication protocol directly to said receiver components, bypassing said antenna.