Estimating parasitic resonances by analysis of the late time response

The experimental investigation of electric systems susceptibility to high-power narrow-band disturbances is problematic. It requires many individual measurements to cover a wide range of frequencies. The knowledge of the resonant frequencies of the system can simplify this task. We estimated the parasitic resonant frequencies of a simple two port network by analysing the transient late time response using the polynomial method on the reversed data series (backward linear prediction method) and the matrix pencil method. Besides the wanted poles, both methods return plenty of poles occurring from the noise. By plausibility considerations the amount of returned poles can be reduced to the relevant poles. We were able to get all parasitic resonant frequencies of the investigated circuit covered by the frequency range of the excitation pulse.