Automated measurement of intermittent signals using a time-domain EMI measurement system

Traditionally emission measurements are carried out in frequency domain using pre- and final scans. Time-domain EMI measurement systems allow to reduce the scan time by orders of magnitude, enabling novel test methods. In this paper the measurement uncertainty for intermittent signals during pre-and final scans is investigated. The effect of the dwell time on the measurement accuracy in the peak and quasipeak detector modes is shown. For conducted emission measurements two test procedures are presented. First method that performs a separate evaluation according to the phase of the LISN, and a second method that performs full maximization. Both methods are used for automated measurement of intermittent and narrowband drifting signals. The total test time is reduced by at least one order of magnitude. Intermittent and narrowband drifting signals, which are still measured today manually, can be measured by the presented procedure automatically. Measurements have been carried out in the frequency range 9 kHz - 1 GHz.