The use of FFT-based measuring receivers for EMI compliance measurements is motivated by the desire to reduce the scan time by several orders of magnitude and to gain additional insights by applying longer measurement times or using enhanced methods like scan spectrogram and persistence mode.

Usage of an appropriate measurement time is the key to comprehensively record the disturbance characteristic of the equipment under test (EUT). The practical use of FFT-based scan spectrogram and persistence mode is demonstrated for automotive measurements.