A.E. Isaev, A.M. Polikarpov
FSUE “VNIIFTRI”, Mendeleevo, Moscow region, Russia;
isaev@vniiftri.ru
Al’manac of Modern Metrology № 3 (43) 2025, pages 8–20
The page of the article in Russian
Abstract. The article proposes a phase-pulse method for measuring the time interval as an alternative to time-of-flight methods for solving the problem of measuring the speed of sound in water medium. An approach based on the absence of dispersion of the speed of sound and the analogy between the cross phase spectrum of signals and the phase incursion during the propagation of a sound wave is considered. The theoretical premises of the method are formulated and an experiment is performed that shows the validity of the proposed approach. The main difference from the known implementations of the time-of-flight method is that the estimate of the propagation time of sound is obtained as an integral characteristic. For this purpose, not individual characteristic points selected in the experiment on time realizations of signals are used, but phase spectra, which are obtained using the entire signal. The estimate of the time interval is obtained by transforming the frequency dependence of the cross phase spectrum into a numerical parameter by applying a linear regression model to it. This is equivalent to averaging over an ensemble of frequencies. Unlike the time interval assessment based on the difference in the steady-state values of radio pulse phases, the use of cross phase spectra allows one to control the quality of the experiment, improve the statistical characteristics of the resulting assessment, and eliminate the subjective factor when selecting characteristic points.
Keywords: sound wave travel time, time-of-flight method, characteristic points of oscillograms, phase-pulse method, phase spectrum, cross phase spectrum, sound wave phase incursion
Full texts of articles are available only in Russian in printed issues of the magazine.
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