Analysis of Nonstationary Emissions for Efficient Characterization of Stochastic EM Fields

Abstract

A statistical approach using field-field correlation functions which is obtained from two-probe time domain measurement is used to characterize the radiation from complex devices. The time-frequency analysis provided by the measurement data has shown that significant emissions may only occur for a few percent of the time and a piecewise stationary model of emissions may be most appropriate. In this paper, a sorting technique is applied to short time segments of the nonstationary time-domain data provided by the measurements. These short time segments are sorted into groups according to the characteristics of the emissions, i.e. different emission processes, with the assumption that the stochastic emissions is stationary within each group (process). The ensemble of time segments associated with each group may then be used to obtain the fieldfield correlations for each process. Results of the analysis give promising insights into how to characterize complex and time dependent systems.

Automatic Segmentation of Nonstationary EM Emission of Electronics Product

“…However, fails to segment the signals in Cases 1 and 4. From the results, we can see that the STE has produced a significant improvement towards the automatic segmentation as compared to STZCR, STK and the manual technique that has been used in [60]. Based on its performance, the STE technique is suitable to be used as a solution to automatic segmentation for the EM emission from an electronic product.…”

“…Figure 1 shows the phenomenon of nonstationary emissions resulting from the operating of a Galileo microcontroller [60]. In the present study, a segmentation technique to achieve piecewise stationary from the nonstationary emissions was carried out manually where signals in the time domain are divided into 16 segments.…”

A review of measurement of electromagnetic emission in electronic product: Techniques and challenges

“…One of the challenges of EM emission analysis in electronic products is related to the emergence of non-stationary emission signals as discussed in [165]- [167]. Figure 14 shows the phenomenon of non-stationary emission from the Galileo operation [168]. The time domain plot is obtained from the measurement consisting of magnetic field probe, digital oscilloscope and Intel Galileo.…”

“…Hafiz et.al proposed a method to achieve piecewise stationary from non-stationary emission signal by segmenting the non-stationary signal from figure 14 manually into 16 segments as shown in figure 15 [168]. The number of segments is fixed to focus more on the sorting technique being used.…”