"Measurement System Design for Resonant Sensors: Excitation, Acquisition and Signal Processing"
Measurement System Design for Resonant Sensors: Excitation, Acquisition and Signal Processing
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This thesis addresses the acquisition and evaluation of resonant sensor signals. With this type of sensors, the desired parameters are typically the resonance frequency and the damping of the resonance, two parameters that can not be measured directly but only derived from acquired signals by mathematical methods. Therefore, the basic properties of resonant sensors and their modeling are presented and the most common methods of obtaining the desired parameters from the acquired signals are discussed.
One of the main subjects of this thesis lies in the development of a new robust algorithm, which is particularly suitable for suppressing the effect of incomplete or erroneous modeling on the calculated parameters.
The second part of this thesis is on the design and realization of a versatile electronic interface for acquiring resonant sensor signals. Based on a thorough analysis of the most common methods, a new approach is presented, where the advantages of established concepts are combined in a novel way, yielding a compact, space?saving interface. To validate this approach in practice, a prototype was built and tested with piezoelectric
thickness shear mode resonators. The results of these measurements are compared to those obtained with a commercially available instrument for acquiring resonant sensor signals.