PURPOSE: To simplify the constitution of an interrogator by phasemodulating the carrier waves of non-modulation transmitted from the interrogator to a radio card by PSK signals and transmitting PSK-PSK signals from the radio card to the interrogator.
CONSTITUTION: In the case of transmitting data from the radio card 1B to the interrogator 1A, the carrier waves are supplied from the interrogator 1A. Then, sub-carrier waves are transmitted from a sub-carrier wave generator 12 to a PSK modulator 11 and the sub-carrier waves are phase-modulated by the data and converted into the PSK signals. The PSK signals are transmitted to the PSK modulator 10. Then, the carrier waves transmitted from the interrogator 1A are phase-modulated and the PSK-PSK signals are generated. The PSK-PSK signals are transmitted through a transmission/reception separator 8 and an antenna 7 to the interrogator 1A. In the interrogator 1A, the PSK-PSK signals transmitted from the radio card 1B are received by the antenna 6 and transmitted from the transmission/reception separator 5 to a distributor 13. Then, a signal level is judged in a data judgement device 18 and data groups are correctly decoded.
OYAMA MITSUZUMI
GUNJI TATSUYA
