Instantaneous impedance spectra of a non-stationary model electrical system

Results of impedance measurements of a non-stationary model electric system are presented. Impedance measurements were realised by the pseudo-white no ise technique. Simultaneous time-frequency analysis of the response signal was performed using the short-time Fourier transformation method. It is sho wn that the measurement method correctly reflects changes of the system inv estigated in the time and frequency domains. (C) 2000 Elsevier Science S.A. All rights reserved.