US Patent 7557711 Interrogator and interrogation system employing the same

The present invention is directed to an interrogator, method of discerning metal and radio frequency identification (RFID) objects, and an interrogation system employing the same. In one embodiment, the interrogator includes a metal sensing subsystem configured to provide a first signal having a signature representing a presence of a metal object, and a RFID sensing subsystem configured to provide a second signal having a signature representing a presence of a RFID object. The interrogator also includes a control and processing subsystem configured to discern a presence of at least one of the metal and RFID objects from one of the first and second signals.