| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve transmitting performance and receiving performance by optimizing a connection condition between an antenna circuit and respective transmitting and receiving circuits. <P>SOLUTION: In the contactless IC card reader/writer for using electromagnetic induction to perform contactless communication and to read and to write data from/in an IC card, an antenna 101 and a turning circuit 102 are provided a parallel resonance circuit comprising at least one loop antenna, a capacitor and a resistance, the receiving circuit is provided with a carrier limiting circuit for suppressing the level of a carrier component of a signal received by the antenna 101 and an input amplification circuit whose input impedance is higher than output impedance of the transmitting circuit, and the transmitting circuit and the tuning circuit 102 are connected by an impedance conversion circuit 110. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
