Sideband diversity reader for electronic identification system

摘要

An electronic radio frequency identification system comprises a reader 12 and a plurality of transponders to be read by the reader. The reader comprises a recovery circuit 32 for recovering and separating an upper sideband 26,12 and a lower sideband 26,11 of a modulated response signal 26,1 from one of the transponders, The reader further comprises an evaluating circuit 38 for evaluating and selecting one of the upper sideband the lower sideband for output to a next stage, based on the evaluation.