Patent ID: 7239657

Claim:
An identification system based upon a microwave signal and capable of suppressing interferences from other systems that transmit a microwave signal spread spectrum technology in the form of frequency hopping or direct sequency, said identification system comprising: a reader for transmitting the microwave signal to an identification device, wherein the identification device modulates at least one information sideband of the microwave signal and reflects the microwave signal and the at least one information sideband back to the reader without new energy being supplied to said microwave signal, wherein data content of the microwave signal reflected by the identification device includes redundancy and the identification device repeats said reflected signal unchanged at least two times in sequence and the signal reflected by the identification device have a longer time duration than an anticipated interference, so that only a part of said reflected signal can be disturbed, and a processor for carrying out a redundancy check on the reflected signal and for comparing said reflected signal unchanged at least two times in sequence, wherein when a deviation is detected between said reflected signal unchanged at least two times in sequence the processor establishes which data bits deviate between said reflected signal unchanged at least two times in sequence and substitutes deviating bits between said reflected signal unchanged at least two times in sequence by carrying out tests until the redundancy check provides an accepted result, whereafter the processor registers the microwave signal as a correct signal.