不同编码激励的超声气体流量测量性能对比  

Performance Comparison of Ultrasonic Gas Flow Metering Systems with Different Coded Excitations

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300072

出　　处：《天津大学学报》2011年第9期768-773,共6页Journal of Tianjin University(Science and Technology)

基　　金：国家高技术研究发展计划(863计划)资助项目(2008AA042207)

摘　　要：对比研究了13位巴克码、2周期7位m序列(均为二进制相位调制)和线性调频3种典型脉冲压缩编码激励下,超声流量测量系统的性能.对接收信号进行脉冲压缩处理后,测得流速与横河1.0精度等级的涡街流量计读数比对,以评估其测量性能.结果表明,m序列激励下脉冲压缩输出旁瓣远高于理论值,而巴克码和线性调频激励时,旁瓣与理论值相差不超过10%.在3～19,m/s的实验流速范围内,相同时宽带宽积条件下,线性调频信号频谱与换能器带宽的匹配度最高,因此有最小的流速标准偏差和读数误差,巴克码次之,m序列最大.This paper reports the performance comparison of ultrasonic gas flow metering systems with three typical pulse compression coded excitations. In addition to the chirp signal, the excitation sequences phase-modulated with 13 bit Barker code and 2 cycles of 7 bit m sequence are investigated. Receiving signals are compressed to calculate the flow rate which can be compared with the reference provided by the Yokogawa vortex flowmeter （reading error ＋ 1.0%）. Results indicate that the main-peak side-lobe ratio （MSR）of the pulse compression output deviates seriously from the theoretical value when using m sequence excitation, while the ratio is not more than 10% when using Barker code and chirp signal. It is also found that at the similar time-bandwidth product and the experimental flow range of 3-19 m/s, the system energized by chirp signal has the smallest flow rate standard deviation as well as the reading error due to its most matching spectrum within the transducer bandwidth.

关 键 词：超声气体流量测量 编码激励 脉冲压缩 性能对比 

分 类 号：TP216[自动化与计算机技术—检测技术与自动化装置]