RADIO FREQUENCY DETECTION AND IDENTIFICATION SYSTEM

摘要

A system (10) is disclosed for detecting the presence of an article. The system (10) includes a transmitter (12) for radiating a first electromagneti c signal at a predetermined primary frequency and a resonant tag (20) secured to the article. The resonant tag generates a second electromagnetic signal in response to receiving the first electromagnetic signal. The second electromagnetic signal has components at the primary frequency and at a predetermined secondary frequency different from the primary frequency. The system also includes a receiver (14) for receiving the second electromagneti c signal and a computer (46) connected to an output (48) of the receiver (14). The computer (46) processes the received second electromagnetic signal and generates an output signal when the secondary frequency is detected in the second electromagnetic signal.