Improved measurement of radiated emissions from moving rail vehicles in the frequency range 9 kHz to 1 GHz

A measurement system has been developed to characterize the radiated electromagnetic interference (EMI) from moving rail vehicles. The system uses multiple spectrum analyzers to make a combination of rapidly repeated frequency domain measurements and time domain measurements using single frequency wide bandwidth envelope detection. Using these techniques, the emissions from a rapidly moving vehicle can be assessed and characterized as narrowband or broadband, continuous or transient. The potential for interference with radiocommunications services can hence be better understood. The system is described and measurement results are presented. Shortfalls in current measurement techniques and advantages of this hybrid technique are discussed.