摘要
针对声时测量精度提高的瓶颈问题,从信号处理的角度,分析了时差法液体超声波流量计中影响声时测量精度的两个主要因素,推导了理论公式,并给出了仿真结果。首先从单声道时差式超声波流量计测量模型出发,介绍了该模型成立的条件,测量原理和其声时测量中存在的问题,然后分析了(1)在高斯白噪声模型下,声时测量误差与系统信噪比的关系;(2)采用过零检测和信号阈值法判定信号到达时刻时,阈值对声时测量误差的影响,并分别给出了声时测量误差与信噪比和检测阈值的关系图。
Two factors affecting accuracy of transit time in ultrasonic liquid flow measurement are ana- lyzed, and the theoretical derivation is made. From the single path model, the principle and the existing problem in transit time measurement are presented. Then, the effect of system SNR on transit time measurement error in white Gaussian noise model and the effect of threshold on transit time measurement error while using zero-crossing and threshold detector are discussed. The simulation result with figures showing the above discussed effects is given.
出处
《声学技术》
CSCD
北大核心
2008年第2期210-213,共4页
Technical Acoustics
关键词
声时测量
信噪比
阈值
transit time measurement
SNR
threshold
