Harmonic Limited Test Waveform for Fast AWIS Dielectric Studies

Paper in proceeding, 2011

Arbitrary Waveform Impedance Spectroscopy (AWIS) has been designed as a versatile tool for dielectric material studies. Among diverse features, it is capable of determining an entire dielectric spectrum from one measurement, provided the test voltage is rich enough in harmonics. However, extremely harmonic-rich test signals limit the measurement accuracy due to aliasing. Aliasing is caused by the data acquisition if there are harmonics above the Nyquist frequency. However, anti-alias filters, the customary solution, are preferably avoided when using AWIS due to high precision requirements. A remaining possibility is to control the aliasing by limiting the test signal harmonic content. In this paper we present an optimized waveform, which can be applied in situations where the test voltage waveform is not dictated by other requirements. In such cases it enables the use of AWIS for fast dielectric studies under rapidly changing environmental conditions.