A comparison of methods of computing power spectra of LDA signals

A number of methods for the computation of power spectra of signals from a laser Doppler anemometer (LDA) have been evaluated, using a hot-wire signal, numerically sampled at irregular intervals. The methods include straightforward FFT, signal reconstruction methods using polynomial or fractal interpolations or Shannon reconstruction, some direct methods of spectral estimation not involving interpolation and two methods relying on slotted autocorrelation function estimates.