Comparison of frequency estimators for interrogation of wireless resonant SAW sensors

Statistical simulation is used to evaluate performance of four different frequency estimators for interrogation of resonant wireless SAW sensors. The first one is based on DFT and quadratic interpolation, the second one employs a weighted least-squares estimate of the phase difference between signal samples. The third and the fourth methods use singular value decomposition and apply a weighted linear predictor in the case of constant sine wave amplitude and an iterative least squares method in the case of decaying sine wave. Numerical receiver model includes additive and phase noises, SAW response limiting, non-linear phase distortions and parasitic SAW responses. Experimental results are also obtained for all the four frequency estimators.