| 摘要 |
<p>PURPOSE: To provide a noncontact IC card system provided with a function for correcting a data error generated in the case of transmitting data from an on-vehicle equipment to a ground equipment and at the time of switching two signals after homodyne detection. CONSTITUTION: When a vehicle enters a tollgate, a CPU 33 in the one vehicle equipment 3 performs radio communication with an on-road equipment through a communication circuit 35 and an antenna 36, adds an error correction code to transmission data such as balance data or the like read from an IC card 32 in an error correction code circuit 60 and performs radio output through the communication circuit 35 and the antenna 36. The ground equipment receives the data from the on-vehicle equipment 3 by a reception antenna, amplifies them in an amplifier, then performs the homodyne detection and performs output to an error correction decoding circuit. The error correction decoding circuit compares the data with correction bits and obtains correlation for homodyne detected signals and when the data are erroneous, they are supplemented by the correction bits and the normal data are reproduced.</p> |
