Shiyuan Zhou

Time-delay estimation via cross third-order cumulant method used in liquid viscosity measurement

The reliability and accuracy of ultrasonic liquid viscosity measurement is directly determined by the reliability and accuracy of time-delay estimation. In practical measurement, noises lead to signal interference and low precision of time-delay estimation. In this paper, Cross Third-order Cumulant Method for time-delay estimation is applied to the measurement of liquid viscosity based on ultrasonic technology. Simulation calculation shows that Cross Third-order Cumulant Method can effectively suppress the effect of correlated Gaussian noise sources comparing with Generalized Cross-correlation Method. Thus, in the case of low SNR, especially when SNR is less than −12dB, this method still can accurately calculate the time delay of the pulse, effectively improving the reliability and the accuracy of viscosity measurement, guaranteeing estimation error reduced more than 20%.

ACOUSTIC FIELD CALCULATION OF ULTRASONIC LINEAR PHASED ARRAY TRANSDUCERS WITH CURVE SURFACE

The focus law and acoustic field computation method about circular arc linear phased array have been discussed in the paper. Acoustic field of transducers is given by the use of the coordinate transformation and an approximation with rectangle element instead of circular arc element, and was validated using Rayleigh‐Sommerfeld Integral and nonparallel multiple Gaussian beam model respectively. The results of two methods match well.