METHOD AND APPARATUS FOR MAINTAINING PSEUDO-SYNCHRONISM IN RFID TAGS

摘要

A method is disclosed of synchronizing at least temporarily, a local clock such as a clock included in an RFID tag, to an external time varying signal. The time varying signal may be included in an electromagnetic interrogation field. The method includes receiving and lag filtering the time varying signal. The method also includes averaging the lag filtered signal and applying the averaged signal to control frequency of the local clock. An apparatus for synchronizing a local clock to an external time varying signal is also disclosed.