System and method for communicating with electronic labels

摘要

The present invention provides a system and method for communicating between an interrogation device and at least one electronic label device. The system includes an interrogation device for generating an interrogation field using an interrogation signal. The interrogation signal contains angle modulation and amplitude modulation such that the amplitude modulation encodes the interrogation signal with information for communication to one or more of the electronic labels. The angle modulation is controllably varied so that the interrogation signal has a frequency spectrum which includes sidebands having reduced amplitudes. The system also includes one or more electronic labels locatable within the interrogation field and capable of detecting and decoding the interrogation field so as to recover the information.