Comparison of FFT and LMS applied to photoacoustic signal detection

摘要

Photoacoustic measurements are quite often performed by means of data acquisition systems that collect samples of the photoacoustic signal, and use the samples for the purpose of calculation of the amplitude of its fundamental frequency. The most common method of such calculations is the FFT, but the amplitude can be also obtained by means of the least mean square (LMS) method. The paper compares properties of both methods from the point of view of their numerical efficiency and errors vs. S/N ratio and number of samples per period of the investigated signal. The discussion shows that in the case of an integer number of periods sampled, results of the FFT and LMS are identical, but due to higher numerical efficiency the LMS method should be used.