Experimental Assessment of Stochastic Signals Through the Power Density Method

The presented methodology allows for the analysis of stochastic signals using an automated near-field measurement system and real-time signal analyzer. In the method below, power density spectra were used to determine random signals once measurement techniques for the near field have been employed to capture stochastic signals. Traditional methods for measurement within the near field identify either the electric (E) or magnetic (H) distributions and, depending on the processing capability of the analyzer used, a description of the time variant signal. It has been observed during the analysis of the measured complex signals that neither the H nor E field distributions have a direct relation to the stochastic field location; as such, a mathematical formula has to be applied to calculate the power density value and position. In the provided method, it is essential that both E and H fields be independently measured in the near field so that the complete complex signal be acquired. Once both fields have been quantified over the same time period and superposition is resolved, the true phase angle can be determined. From the resulting data a Poynting vector can be calculated and post processing algorithms applied to determine the stochastic signals' physical location and power density value. This technique can, through a backscatter analysis, determine if any signal returns to the source, so as to assess if there are any impacts on Signal Integrity or Power Integrity.