Evaluation results of high-speed modem for EMI reduction automotive use

This report describes a high-speed LAN (local area network) for automotive use which eliminates EMI (electromagnetic interference) noise. The automotive LAN is facing two problems due to acceleration of data transfer speed. One is an interference problem in the AM/FM radio receiver. High-speed data transmission makes the baseband frequency higher and higher. EMI energy given out of carrier signal has been several hundred times higher compared to ´command communication´. Another problem is communication interference by induction noise from the ignition and so on. The authors solved the above problems with the development of a 5 MHz FSK (frequency shift keying) modulation circuit. In this paper, the authors explain the technology of the 5 MHz FSK modulation circuit and evaluate results from actual car use.