Device modeling for nonstationary conducted emissions based on frequency- and time-domain measurements

In this paper, a new circuit model and measurement methodology for the characterization of electric and electronic devices emitting nonstationary (as well as stationary) conducted emissions (CEs) are presented. The new circuit model combines a frequency-domain characterization of the passive behavior of a device, obtained from its S-parameter measurements, with a characterization of the CE sources obtained from time-domain measurements. It overcomes limitations of previous works providing a robust, efficient, and mathematically accurate description of the interference generation process, in particular in the nonstationary case. The validity and utility of this methodology are assessed by comparing its predictions with measurements performed according to standard procedures. Finally, it is shown how it can be effectively used in the computer-aided design of power-line filters for devices emitting nonstationary CE.