Accurate LDA-spectra by resampling and ARMA-modeling

With Laser-Doppler Anemometry (LDA) the velocity of gases and liquids is measured without disturbing the flow. The velocity signal is sampled at irregular intervals; a regularly resampled signal is extracted using Nearest Neighbor Resampling or Linear Interpolation. From the resampled data the spectrum is estimated using AR-MA time series modeling. AR-MA modeling yields a more accurate description of the spectral structure than the best Windowed Periodogram. The accuracy of the spectral description is established with an objective measure: the model error at time scale T.