A novel multichannel amplitude probability distribution for a time-domain EMI measurement system according to CISPR 16-1-1

Traditionally, EMI measurements have been performed by EMI receivers, using defined IF bandwidths and detector modes like quasi-peak, peak and average. With the introduction of the Amplitude Probability Distribution function in CISPR 16-1-1 a new weighting method to protect analogue and digital communication standards has become available. However the product standards specifies that the measurement of the APD measuring function must be performed at a large number of frequencies, and evaluation according to specified limits must be performed. In this paper a novel time-domain EMI measurement system from 9 kHz - 18 GHz is presented, which allows to perform measurements of the Amplitude Probability Density function at several thousands frequency points at the same time. The architecture of a multichannel APD System using Short-term FFT is presented. Such a measurement system allows to make automated scans over large frequency spans. Methods to show an evaluation of such measurements are presented. Measurements have been performed on DVB-T Signals. Correlation with traditional EMC Measurements in the peak and average detector mode are shown.