## Abstract

Measuring of parameters of two-phase flows usually needs the contactless measuring techniques to be used together with advanced methods of signal processing. One of these techniques, which are employed for many years in measurements of liquid-gas, liquid-solids and gas-solid particles flows is a method of gamma-ray densitometry. Frequently in such measurements the mutually delayed stochastic signals are received from the scintillation detectors. For the time delay estimation the well-known cross-correlation method is usually used due to the random nature of the signals and presence of disturbances. This paper describes a proposition of use of Hilbert Transform to time delay estimation in radioisotope measurements of two-phase flow. It presents results of simulation study of the modified cross-correlation method, in which the Hilbert Transform of one measured signal is used. The simulations have been carried out for models of stochastic signals, corresponding to signals received in investigations of liquid-gas flow through horizontal pipeline, carried out with use of gamma-ray absorption technique. It has been stated that the described method provides better metrological properties than classical cross-correlation.

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