摘要
针对在实际的超声波传输时间的测量中,接收波形起始点不能确定,导致脉冲计数不准的问题,提出全相位相位差时延估计方法,根据全相位的"时不变特性"得到超声波信号的时延估计。首先分别对超声波正逆程信号做全相位频谱分析,根据频谱分析的结果计算出正逆程信号的相位差,再根据相位差与时间差的关系推导出时间差,得到超声波信号的时延估计。当超声波流量计的基波频率为1 MHz,采样频率为12. 5 MHz,采样点数为507,A/D采样位数为11位时,用该算法分别求超声波大流量数据、干扰数据、静态水数据的时间差,实验结果表明,该时延估计方法能有效地减小超声波传输时间的测量误差,测量误差分别约为33、44、6. 5 ns,比数据延拓式相关法的时间差测量精度高,从而提高超声波流量计的流量测量精度。
For the measurement of the actual ultrasonic transmission time, the starting point of the received waveform cannot be determined, resulting in the problem of inaccurate pulse counting, the all-phase phase difference time delay estimation method is proposed, which obtains the time delay estimation of an ultrasonic signal according to the “time-invariant characteristic” of the all-phase. Firstly, the all-phase spectrum analysis was performed on the ultrasonic forward and reverse signals respectively, and calculated the phase difference of the signals based on the results of the spectrum analysis. Then, the time difference was derived according to the relationship between the phase difference and the time difference, and the time delay estimation of the ultrasonic signal is obtained. When the fundamental frequency of the ultrasonic flow meter signal was 1 MHz, the sampling frequency was 12.5 MHz, the number of sampling points was 507 and the A/D sample number was 11, calculating the time difference of the ultrasonic large flow data, the interference data and the static water data respectively. The verification results show that this time delay estimation method can effectively reduce the measurement error of ultrasonic transmission time, the error is about 33,44,6.5 ns respectively, which is more accurate than the data extension correlation method, thus to improve the flow measurement accuracy of ultrasonic flowmeter.
作者
黄晓红
许先凤
HUANG Xiao-hong;XU Xian-feng(Information Engineering College 1, Tangshan 063200, China;Electrical Engineering College, North China University of Science and Technology, Tangshan 063200, China)
出处
《科学技术与工程》
北大核心
2018年第36期211-215,共5页
Science Technology and Engineering
基金
河北省自然科学基金(E2016209357)
河北省钢铁联合基金资助
关键词
相位差
全相位频谱分析
时间差
超声波流量计
phase difference
all-phase spectrum analysis
time difference
ultrasonic flow meter
