Non-contact type IC card, system and data transmission method therefor

摘要

A non-contact type IC card with a simplified circuit arrangement which can select one of the PSK- and FSK-modulations at data transmission. A resonance frequency switching section 40 is provided to halve the resonance frequency of a transmission and reception antenna 4. In the case of the PSK-modulation, the resonance frequency of the transmission and reception antenna 4 is made to become 1/2 during one period of the original frequency at a modulation point so that the phase inverts for the phase modulation. On the other hand, in the case of the FSK modulation, for the frequency modulation the frequency is switched over in accordance with the variation of the data. A PFSEL switch 11 carries out the switching between both the modulations. <IMAGE>