A Method for Measuring Ultrasonic Echo Propagation Time

Abstract

The invention discloses a method for measuring the propagation time of an ultrasonic echo. The propagation time can be obtained by adopting corresponding fundamental wave signals aiming at different flow rates to carry out cross-correlation operations and search the peak values of cross-correlation functions. As the fundamental wave signals at different flow rates are actual data extracted in a dynamic measurement process, the fundamental wave signals have higher precision and are capable of reflecting actual conditions. The fundamental wave signals at corresponding flow rates are adopted to carry out the cross-correlation operations, thereby, the propagation time of dynamic ultrasonic signals is calculated, the measuring errors are greatly reduced, and the uncertainty of a measuring result is reduced. Moreover, the cross-correlation operations are carried out by utilizing the similarity among the signals, the higher the similarity is, the higher the precision, and a non-correlation noise suppression effect is obvious. The invention also provides a novel fundamental wave extraction mode, which is characterized in that the fundamental wave signals are accurately obtained through a set energy constraint boundary. Compared with the mode that a threshold method is adopted to obtain the arrival time of the echo so as to extract the fundamental wave signals, the initial segments of the fundamental wave signals extracted by the novel fundamental wave extraction mode disclosed by the invention are more accurate.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic flow measurement, and in particular relates to a method for measuring ultrasonic echo propagation time in an ultrasonic flowmeter. Background technique [0002] Ultrasonic flowmeter is a new type of flow measuring instrument that uses ultrasonic signals to carry flow velocity information when propagating in fluid to calculate fluid velocity, and then calculate the flow rate. It has the advantages of non-contact, high measurement accuracy, and convenient installation and maintenance. [0003] Ultrasonic echo propagation time refers to the time interval between the transmission of the ultrasonic transducer at the transmitting end and the reception of the signal by the transducer at the receiving end, such as figure 1 As shown, T is the real ultrasonic echo propagation time, and T' is the actual measured propagation time. Usually the transmitted signal is a regular waveform with a high signal-to-...

AI Technical Summary

Problems solved by technology

The obvious disadvantage of the threshold method is: due to the change of parameters such as medium flow velocity, temperature and pressure in the pipeline, the signal fluctuates greatly, and the noise signal is superimposed on the sound wave, which is prone to false triggering or non-triggering, resulting in large measurement deviations

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