Optical interface between receiver and tag response signal analyser in RFID system for detecting low power resonant tags

摘要

In a radio frequency identification (RFID) system using intelligent tags, amplitude and phase noise is minimized by using a low noise crystal oscillator (70) having an output frequency which is an integer multiple of the desired RF field frequency, then dividing this frequency using cascaded flip-flops for the frequency divider (72). Both outputs of the final stage flip-flop drive the transmitter antenna (34) to produce a continuous wave signal. In a radio frequency identification (RFID) system using intelligent tags, amplitude and phase noise is minimized by using a low noise crystal oscillator (70) having an output frequency which is an integer multiple of the desired RF field frequency, then dividing this frequency using cascaded flip-flops for the frequency divider (72). Both outputs of the final stage flip-flop drive the transmitter antenna (34) to produce a continuous wave signal.