Comparison of time domain and frequency domain electromagnetic susceptibility testing

Electromagnetic susceptibility testing in the frequency domain requires a lot of test equipment and much time for the examination in a wide frequency range, from a few kHz to several hundreds of MHz. Frequency steps must be small enough to allow the indication of resonance frequencies. Fourier transformation shows the correlation between time domain and frequency domain. By this transformation, results of susceptibility tests with nanosecond impulses can be analyzed in the frequency domain. Frequency responses of simple devices under test are calculated from the results of impulse testing in the time domain. They show the same characteristics as the results of frequency domain tests. The impulse test method seems to be a simple and fast tool to find the weak points of electric systems against electromagnetic radiation. Because of their importance for susceptibility of electronic circuits, investigations on cables and conductors on printed-circuit boards (PCB) are put forward. Further on, the presented comparison of time domain and frequency domain test methods can be taken into account for emission measurements of electronic equipment measured with ordinary TEM (or GTEM) cells in the time domain