| 摘要 |
PURPOSE:To change identification number easily, by providing a device for modulation and a device which generates a modulating signal corresponding to an identification number as different structures, and using a couple of transmission lines which couple both devices togeher for both power supply and signal transmission. CONSTITUTION:Parallel numeric data corresponding to an identification number set in an identification number setter 14 characteristically to the 2nd device 22 is applied to a parallel-series converter 11 according timing controlled by a control circuit 9. Serially converted numeric data is converted by a voltage-frequency converter 12 into an FSK signal of frequency suitable to transmission and transmitted to the composing and separating device 15 of the 1st device 21 while superposed on a DC component from the 1st device 21. A modulator 13 modulates a high frequency signal received by an on-car device through an antenna 6 by the FSK signal from said voltage-frequency converter 12. This modulated high-frequency signal is sent back to a ground-side device through a transmitting antenna 7. |
