摘要
传播时间法超声流量测量中使用相关时延估计需注意回波混叠效应。在矩形窗猝发脉冲激励下,进行了流速范围从3.0m/s到18.9m/s的管道实流实验和距离范围从50mm到200mm的静态测距实验,研究回波混叠对测量的影响。前者传感器距离固定,通过调节激励长度改变回波混叠程度;后者激励长度固定,通过调节传感器间距改变回波混叠程度。结果表明,时延估计性能随混叠程度增大而降低。理论定性分析进一步说明,混叠效应会产生成对回波,使相关输出形状失真,是导致时延估计精度变差的主因。
The effect of overlapped echoes on time-of-flight estimation by correlation in transit time ultrasonic flow measurement is discussed. The realistic flow experiment from 3.0m/s to 18.9m/s and the ranging experiment from 50mm to 200mm at zero flow are conducted to evaluate the influence of the overlapped echoes,both using the tone burst excitation with its rectangular envelope. Lengths of the echoes are adjusted by changing the duration of the excitation and/or the distance between the transducers to simulate the overlap at different levels. The results show that the performances of time delay estimation,including the bias and the standard deviation,become worse as the echoes overlap seriously with the receiving signal. And the further theoretical derivation qualitatively demonstrates that the overlap could introduce a paired-echo which results in the distortion of the correlation output and is responsible for the degeneration of the time delay estimation.
出处
《传感技术学报》
CAS
CSCD
北大核心
2010年第4期553-557,共5页
Chinese Journal of Sensors and Actuators
基金
863计划资助(2008AA042207)"典型行业高性能传感器"重点项目之"过程控制流量传感器"
关键词
超声流量测量
相关
时延估计
回波混叠
ultrasonic flow measurement
correlation
time delay estimation
echo overlap
