Noise and Aliasing Aspects in a Multiharmonic-Dielectric-Response-Measurement System

Dielectric-response measurements are commonly performed with frequency-domain spectroscopy, polarization/depolarization-current measurements, or return-voltage measurements. These techniques operate in a frequency or time domain, and all have high requirements on the voltage source in order to acquire accurate results. This limits dielectric-response measurements to offline applications. A new technique, which is called arbitrary-waveform-impedance spectroscopy, has been developed, which makes use of the harmonics of any voltage waveform to perform dielectric-response measurements. The technique provides possibilities for online measurements facilitating the monitoring of materials and components in high-voltage applications. Here, the different aspects of the measurement system are presented, including circuit modeling, normalization, and discussions on aliasing and noise; all of them are necessary to control in order to perform accurate measurements.