Why Frequency Domain Tests Like IEC 61000-4-19 Are Not Valid; a Call for Time Domain Testing

Abstract

Testing of electrical and electronic equipment is generally performed using frequency domain tests like the IEC 61000-4-19. This standard covers the immunity to conducted, differential mode disturbances and signaling in the frequency range from 2 kHz to 150 kHz. Previous research describes several electromagnetic interference (EMI) cases in this frequency range, which cover pulsed, fast changing, current waveforms. For example cases are described where static energy meters can give misreadings when loaded with pulsed currents. Fast changing time domain signals are not covered by the standards. In this paper it is shown that the current frequency domain tests are not sufficient to determine the equipment’s immunity, because of for instance non-linear effects, including saturation, digital sampling error effects and other non linear time invariant (LTI) effects.