Impulsive debut [EMC testing]

Electromagnetic compatibility (EMC) testing of any electronic device can be a time-consuming and expensive process. With the ever-increasing number of such devices and reduced product lifecycles, the EMC test burden on manufacturers is growing. A variety of EMC standards exist to cover different equipment types and, historically, most cover the 30 MHz to 1 GHz frequency range. Some go beyond this and future standards may cover the frequency range up to 18 GHz. Today's EMC test methods rely on swept spectrum analysis techniques and have changed little for several decades. Consequently, there is a need for a change in the way EMC testing is performed to reduce the time taken and bring the tests in line with today's digital world. Ofcom, the regulator for the UK communications industry, recently completed a project to investigate the use of time domain techniques for EMC measurement and, in particular, to study the use of such techniques for measuring impulsive emissions. In contrast to the swept frequency approach, the time domain technique uses an ultra fast sampling system to capture a burst of the signal, and uses fast Fourier transform (FFT) techniques to compute the spectral characteristics from the burst. The article provides a summary of the research into time domain techniques.