基于虚拟仪器的超声波高精度测时系统

提出了一种基于相位法测量超声波信号时间延迟的测量技术,建立了超声波信号飞行时间测量的数学模型｡针对超声波测量要求响应速度快､单次测量精度高的要求,依据信号相位匹配原理对超声波信号时延估计的理论和方法进行了理论推导与仿真,得出基于相位法的时间测量精度受接收信号信噪比的影响｡通过虚拟仪器平台的实验,表明该测量系统的信号传播时间测量具有ns级的测量精度｡
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  Accurate Measurement Technology of Ultrasonic Based on Virtual Instrument

ZHANG Gang1,YANG Xiao-ping1,XIAO Cong2

(1.Shenzhen Graduate School,HIT,Shenzhen 518055,China;2.Shenzhen Gentos Company,Shenzhen 518055,China)

Abstract:The measurement technology of the ultrasonic travel time of the ultrasonic based on phasematched theory was presented.On the basis of the mathematical model of travel time measurement,the high precision sinusoidal signal's phase parameter was estimated.When the starting point of the sinusoidal signal was detected,the ultrasonic'accurate transmitting time was obtained.Theoretical and simulation results show not only noise can be suppressed,but also the accuracy of the estimated parameters is improved in the case of lower ratio of signal to noise.Experiment results based on virtual instrument confirmed that the precision of acoustic travel time blow 1 nanosecond.

Key words:ultrasonic;travel time;phase estimation;virtual instrument