Accurate Fitting Techniques for QCM-D Response Analysis

In this work we propose use of three advanced digital fitting algorithms for the extraction of frequency and time constant of QCM-D response signals. The proposed algorithms provide very low estimation errors so to reach the challenging resolution and accuracy required in QCM applications. The algorithms' performance was characterized using simulated, emulated, and experimental datasets. The paper analyzes the dependence of the estimation accuracy both on the noise level and on the measurement conditions in terms of mechanical load. It is shown that with a smart selection of the initial conditions for the fitting algorithms, an estimation error lower than 5 Hz is reached for the series frequency in the presence of typical noise levels, even in the presence of large mechanical loads.