巴克码激励的超声气体流量测量研究  

Ultrasonic Gas Flow Metering with Barker Coded Excitation

作　　者：蒲诚[1] 张涛[1] 綦磊[1] 

机构地区：[1]天津大学电气与自动化工程学院天津市过程检测与控制重点实验室,天津300072

出　　处：《计量学报》2011年第4期318-323,共6页Acta Metrologica Sinica

摘　　要：提出了一种用“编码激励＋相关测时”的超声气体流量测量方法。理论分析和数值仿真均表明，相同信噪比条件下，与传统的门限电平法及猝发脉冲激励相关法相比，巴克编码激励相关法的时延估计量方差具有更低的克拉美罗下界。采用标准表法标定实验，在200～1200m3／h范围内对比研究了巴克序列二进制相位调制激励相关和猝发脉冲激励相关的超声流量测量性能，前者测得流速的标准偏差和测量误差明显优于后者。A method using coded excitations combined with correlation to estimate the time-of-flight in transit time ultrasonic gas flowmeters is presented. By theoretical derivation and numrical simulation, it shows that the system with Barker coded excitation has a lower Cramer-Rao Bound of time-of-flight estimation, compared with the traditional threshold method or correlation with tone burst excitation, assuming the same signal to noise ratio （ SNR）. An ultrasonic gas flow metering system with Barker code binary phase-shifted keying （2PSK） excitation as well as tone burst is designed on FPGA and calibrated by a standard vortex flowmeter with 1% accuracy from 200 to 1200 m3/h. The results, being in close agreement with the simulations, show that the measuring accuracy and repeatability of the system with Barker coded excitation is better than that of the traditional one.

关 键 词：计量学 超声气体流量测量 巴克编码激励 时延估计 相关 

分 类 号：TP937[自动化与计算机技术]