ANALYSIS OF THE RANDOM ERRORS OF DIGITAL ALGORITHMS FOR MEASURING THEFREQUENCY OF LASER-DOPPLER ANEMOMETERS BY NUMERICAL MODELING

An analysis is made of the errors of digital algorithms for measuring the frequency of the Doppler signal of a laser-Doppler anemometer (LDA ) by numerical modeling. An examination is made of methods of evaluati ng the period of the high-frequency duty cycle of a single-particle si gnal from an LDA with respect to the coordinates of the ''zeros'' of t he process. Methods of evaluating the frequency of the signal from the position of the maximum of the modulus of spectral density are also d iscussed. Results are presented from studies of the dependence of the measurement error on the parameters of a discretized LDA signal and th e signal/noise ratio. The conditions necessary for restricting the max imum measurement error to 0.1-0.3% are determined.