导　　师： 郭建中

学科专业： 070206

授予学位： 硕士

作　　者： ;

机构地区： 陕西师范大学

摘　　要： 超声换能器的阻抗性能参数测定是换能器性能测量中的一个重要内容,换能器阻抗特性参数的测量主要有传输线路法和导纳圆图法两种。导纳圆图法测量换能器的阻抗特性可达很高精度,所以目前科研与工程领域应用的绝大部分超声换能器阻抗分析仪是采用了此方法。但这种阻抗分析仪的价格非常昂贵,广泛应用比较困难。 本文探讨各种换能器参数测量方法的优点,基于虚拟仪器设计超声换能器阻抗分析仪,主要进行了以下几个方面研究： /(1/)探讨相位检测技术在换能器性能测量中的应用,根据国家制定的测量标准对传统导纳圆图法中电压、电流信号的相位差测量方法加以改进,设计常用换能器工作的频率范围内的电流信号采集电路,采用虚拟仪器技术构建相关分析法测量相位差,提高精度。 /(2/)研究仪器控制方法,采用信号发生器和数字示波器等实验室通用的设备作为超声换能器阻抗分析仪的主要硬件部分,通过LabVIEW软件编程,控制信号发生器扫频信号输出以及数字示波器的信号采集,组成阻抗分析仪的信号产生与接收系统。 /(3/)研究传统导纳圆图法测量换能器阻抗特性的计算方法,提出系统设计时消除随机噪声影响的方法,通过三次样条拟合的方法消除系统无效信号对计算结果的影响。 /(4/)设计了超声换能器阻抗分析仪软件平台,开发系统的信号发生器控制模块、示波器数据采集模块、信号滤波模块、相位检测模块、数据计算与处理模块和数据保存模块。 经过实际测量及结构比对表明,本文基于虚拟仪器设计的超声换能器阻抗分析仪具有如下几个方面优点： /(1/)通过与商业产品的阻抗分析仪测量对比,本设计的导纳圆图法测量阻抗特性的具有相同数量级的精度。 /(2/)采用虚拟仪器技术进行系统设计,弥补线路连接复杂的不足,利用实验室常用仪器构建系统,降低系统成本提高了应用范围。 /(3/)将高精度的相关分析法测量相位的方法引入到系统中,很好地解决了传统的相位检测技术误差大的缺点。 Measurement about the impedance parameters of ultrasonic transducer is an important content in the transducer measurement. There are two main methods to measure the impedance characteristic parameters of transducer:transmission line method and the admittance circle diagram. Measuring transducer impedance characteristic by admittance circle diagram will be very accuracy. Therefore, currently, this method is applied in most of the ultrasonic transducer impedance analyzer in science research and engineering field. But this impedance analyzer is very expensive, so it is difficult to be widely used. This paper discusses the advantages of various transducer parameters measurement method. Basing on virtual instrument to design ultrasonic transducer impedance analyzer, it researches mainly in the following aspects: /(1/) Discuss the application of phase detecting technology in the transducer measurement, according to the measuring standards made by country, improve the methods of voltage and current signals of phase detection in the traditional admittance circle diagram, design signal usually used the frequency range that transducer works to acquire circuit, and measure the phase by using the virtual instrument technology to construct relevant analysis and improve accuracy. /(2/) Research the method of controlling instrument,use the signal generator and digital oscilloscope and other common laboratory equipments as the major hardware of ultrasonic transducer impedance analyzer, by Lab VIEW software programming, control sweeping signal output from signal generator and the signal acquisition of digital oscilloscope, and compose signal generator and receiver system of impedance analyzer. /(3/) Research the calculated methods about measuring transducer impedance by traditional admittance circle diagram, propose the method of eliminating random noise when system is designed, eliminate the influence to the calculated results of the system ineffective signal by cubic spline fitting method. /(4/) This paper designed the software platform about ultrasonic transducer impedance analyzer, developed the module of system controlling signal generator, oscilloscope data acquisition module, signal filtering module, phase detection module, data calculation and processing module and data storage module. After the measurement and structural comparison, it shows that the ultrasonic transducer impedance analyzer which is designed based on Virtual Instrument has the following merits: /(1/) By comparing with the measurement of commercial products impedance analysis, the admittance circle diagram of measuring impedance designed in the paper has the same level accuracy. /(2/) Using the virtual instrument technology to design system, makes up the complex line connections, using common laboratory instrument to construct system reduces the costs of system and the application range. /(3/) Introducing the high-precision correlated analysis method of measuring the phase to the system, solves well the shortcomings that there are large errors in traditional phase detection.

关 键 词： 超声换能器 虚拟仪器 阻抗分析仪

分 类 号： [TB552]

领　　域： [理学] [理学]