The Elements Research On Remote Transmission Of Vehicle Condition Signal

It is difficult to carry through vehicle remote condition monitoring because of the vehicle's feature of distributing, moving and little worth. Now in China there are hardly the smart monitoring devices equipped at vehicle in real-time, especially at the native-made vehicles. The technology of vehicle remote condition monitoring not only adapts to the tendency that the computer technology is fusion with the information technology and country-wide communication system, but also become a new area of research, application and exploitation for ITS (Intelligence Transportation System). So there is practical meaning for studying it.In this paper the schemes of vehicle remote condition monitoring based on FM system and GSM system have been brought forward after analyzing the development and application of the technology in the state-of-the art. Considering as the China situation of high increasing-rate of passenger car and high possession-rate of GSM mobile telephone, the research items are follows:(1) After analyzing math model and signal transmission of mobile channel as well as simulating the characteristic of multi-path transmission, the result that signal transmission quality is affected by mobile channel characteristic remarkably has been proved.(2) The mobile transmission tests for analog signal have been processed. The characteristic of amplitude-frequency and phase-frequency of mobile channel has been achieved. Later the tests researches on diesel engine black vibration acceleration signal have also been carried out. Conclusions are as follows: â‘  Comparingreceiving signal with sending signal transmitted by the two systems--the FMsystem and GSM system, there is attenuation in amplitude domain, delay in time domain, biggish changes of signal feature in time-domain and frequency-domain while the key characteristic frequency of signal is holding. â‘¡ The frequency characteristic is important for developing vehicle remote monitoring system and analyzing remote monitoring signal. â‘¢ Different mobile transmitting system has different ideal analog signal frequency bands for mobile transmission: The domain from 100 Hz to 4000 Hz is for FM system meanwhile the domain from 300 Hz to 3500 Hz for GSM system.(3) For compensating the feature change of time-domain and frequency-domain,...