Impedance measurement using multiharmonic least-squares waveform fitting algorithm

In this paper, a multiharmonic least-squares waveform fitting algorithm is used to measure impedances. By using analog to digital converters, a function generator, a reference impedance and the fitting algorithm, we show that it is possible to obtain the frequency response of a unknown linear impedance at the frequencies that correspond to the harmonics of the stimulus input signal.

Results show that, with a 400 Hz triangular signal, harmonics up to the 49th can be used to measure the impedance frequency response of a parallel RLC circuit with experimental standard deviations below 1.5% for the impedance magnitude and 1° for the impedance phase.