| 摘要 |
<P>PROBLEM TO BE SOLVED: To use the most efficient frequency in power supply and to achieve high speed communication at a frequency higher than the most efficient frequency in bi-directional data communication. <P>SOLUTION: A power supply coil 201 of an IC card 2 is electromagnetically coupled to a power supply coil of an IC card reader, electromagnetic waves of 5 MHz for power supply are received from the IC card reader by the power supply coil 201 and voltage for driving the IC card 2 is generated. An oscillation circuit 232 which oscillates at 50 MHz is incorporated in the IC card 2 and operation timing of the IC card 2 is controlled by a clock signal of 50 MHz. Operation timing of the IC card reader is controlled by the clock signal of 50 MHz. Communication coils 206, 215 of the IC card 2 are electromagnetically coupled to a communication coil of the IC card reader and data communication is performed by carrier frequency of 50 MHz between the IC card 2 and the IC card reader. <P>COPYRIGHT: (C)2008,JPO&INPIT |
