Simplifying Cole-impedance extraction from the current-excited step response

A simplified expression for the current-excited step response of the Cole impedance model which significantly reduces the numerical complexity required to extract the impedance parameters using a nonlinear least squares fitting is presented. MATLAB simulations show reductions in extraction times up to 47.5%, without reducing extraction accuracy and are verified experimentally on an ideal Cole-model and fruits used as the Cole impedances showing less than 2% relative error between simulated responses (using the extracted impedance parameters) and the experimental results over the entire dataset.