Impedance Measurement Using Wide-Band Signals

Measuring the impedance of dynamic systems requires fast measurement techniques to prevent any significant impedance changes that render the impedance time-variant. However, measurement by means of conventional frequency sweep methods are time-consuming, specially at low frequencies where many important processes of electrochemical systems take place, and the validity of the linear time invariance (LTI) assumption of the measured data becomes questionable. In this work, we present the use of a compact wide-band precision measurement system based on a new set of wide-band signals not used before in the field of impedance measurement. Such signals provide a relatively flat power spectral magnitude over a wide bandwidth while maintaining a controllable time-domain maximum amplitude swing. The proposed signals are used to successfully measure a standard precision calibration cell over eight frequency decades.