Analysis of non-stationary electrochemical oscillations emerges utilization of the techniques allowing an observation of time evolution of their parameters such as instantaneous frequency, amplitude or frequency band. An algorithm of extraction of these parameters can be based on one of linear or quadratic time-frequency representations of oscillations record. In this paper, the authors present representatives of such transformations (Choi-Williams and Cone-shaped) originating from one of the most popular joint time-frequency energy distribution-Wigner-Ville distribution. Short introduction to the mathematics of the topic discussed is provided, then the authors present an example of application in the analysis of current oscillations of copper dissolution process. (C) 2003 Elsevier Science Ltd. All rights reserved.