OPTIMIZATION OF THE PERTURBATION SIGNAL FOR ELECTROCHEMICAL IMPEDANCESPECTROSCOPY IN THE TIME-DOMAIN

The choice of the perturbation wave form is of crucial importance for reliable electrochemical impedance spectroscopy measurements based on the fast Fourier transformation. Using numerical simulation, arguments and results are presented for the choice and the optimization of a pe rturbation signal constructed as a superposition of discrete sine wave s with selected frequencies. Two possible ways to optimize the perturb ation for better noise immunity are described choosing proper values f or the phases of the individual sine waves, minimal perturbation signa l amplitudes can be obtained which improve the quality of impedance da ta by 25%. By introducing response-sensitive amplitudes an improvement in the quality of data by a factor of 4-5 can be reached in the low f requency range. A new technique for single-pulse measurements with con tinuous perturbations that assures a steady-state response and better accuracy at high capacitive and/or inductive samples is also described .