| 摘要 |
Provided is a reader/writer capable of discriminating the arraying order of an RFID tag and the moving direction with respect to an antenna. This reader/writer (50) is constituted to comprise a PLL circuit (1) for synchronizing the phase of the output signal of a VCO (2) with the phase of a reference input signal, the VCO (2) for oscillating a predetermined frequency on the basis of the control voltage of the PLL circuit (1), a modulator (3) for modulating the signal transmitted from the VCO (2), into a microwave, a circulator (5) for deciding the direction by the direction of the microwave, an antenna (6) for transmitting the microwave and receiving a reflected wave from a tag (7), a mixer (9) for demodulating a sin wave, a mixer (11) for demodulating a cos wave, a BPF (12) for passing only a predetermined frequency component from the signal of the mixer (9), a BPF (13) for passing only a predetermined frequency component from the signal of the mixer (11), and an operation unit (15) for computing the phase from an A/D converter (14) and an A/D converter (16). |
