Theoretical investigation of applicability and limitations of advanced noise reduction methods for wavelength modulation spectroscopy

In this study, the applicability and limitations of several statistical and mathematical methods for noise reduction in wavelength modulation spectroscopy are analyzed. Background noise is simulated for different frequencies and frequency confinement. The noise is added to an absorption line of varying amplitude. The noise reduction methods (NRMs) are applied to the simulated signals and their performances are analyzed and compared. All NRMs show great increase in signal to noise ratio (SNR) while keeping bias low under certain conditions of the simulated signal. For each NRM the subspace of best performance is summarized and highlighted. Little to no overlap is found between these subspaces. Therefore, the optimal NRM strongly depends on measurement conditions and NRM quality cannot be compared in a general context.