A novel Approach for Impedance Spectrum Estimation: the Local Polynomial Method

Measuring the Electrical Impedance steady-state response of a time varying system by Impedance Spectroscopy is not always useful especially when the dynamic behavior itself is pretended to be characterized. In contrast to the frequency-sweep EIS approach, measuring with wide band spectral signals enables to reduce the measuring time. Nevertheless, the measurements are prone to the influence of the transients introduced by the system dynamics. This paper presents a novel approach for impedance frequency response estimation, based on the Local Polynomial Method (LPM). The theory presented is supported by a set of simulations, which show the improvement in accuracy of the impedance spectrum estimation with respect to the classical spectral estimation methods based on auto/cross correlation using windows.