1、毕业设计（论文）材料之二（2）安徽工程大学机电学院 本科毕业设计( 论文) 开题报告题目： LabVIEW 在电子线路课程中的应用课 题 类 型： 设计 实验研究 论文学 生 姓 名： 魏 晨学 号： 3102102245 专 业 班 级： 电信 2102教 学 单 位： 电气工程系指 导 教 师： 周 鹏 （讲师） 开 题 时 间： 2014 年 3 月 21 日 2014 年 3 月 19 日一、本课题的研究意义、研究现状和发展趋势（文献综述）研究意义：虚拟仪器（VI）是计算机辅助测试（CAT）的最新发展，它充分利用快速发展的计算机及通信网络技术来提高测试计量仪器设备的功能、性能和应用范围
2、，为用户定义和构造自己的测试仪器系统提供了全新的解决方案。虚拟仪器并不完全等同于计算机辅助测试，它是一种基于信号采集与分析理论、具有标准化软硬件及其接口和良好集成性与柔性的仪器系统，是一种新的测试仪器标准和技术规范。虚拟仪器技术构建的应变测试仪的诸多优点表明，虚拟仪器系统具有重要的现实意义和推广价值, 是传统应变测量仪器的理想替代产品。随着计算机网络技术的迅速发展，将为虚拟仪器提供更强大的功能，即可以实现远距离的网络化虚拟仪器实时测试。只要在应变测量系统中添加网络功能模块，借助于宽带网络技术可以很容易的实现远距离实时测试，这是基于虚拟仪器技术构建的应变测试系统今后的发展方向。相信将来的应变测量
3、系统一定是虚拟仪器技术与计算机网络技术相结合的系统，其测试功能会更强大，精度会更高，应用会更广。本课题研究的主要要求：熟练运用 LabVIEW 软件，运用 G 语言实现数据的采集，分析处理并得出结果，并且结合 LabVIEW 在是模拟电路和数字电路中应用的具体的实例进行分析设计，并写出设计的方案和仿真的结果进行论证。研究现状和发展趋势：LabVIEW 是一种程序开发环境，由美国国家仪器（NI ）公司研制开发的，类似于 C 和 Basic 开发环境，但是 LabVIEW 与其他计算机语言的显著区别是：其他计算机语言都是采用基于文本的语言产生代码，而 LabVIEW 使用的是图形化编辑语言 G 编
4、写程序，产生的程序是框图的形式。LabVIEW 软件是 NI 设计平台的核心，也是开发测量或控制系统的理想选择。LabVIEW 开发环境集成了工程师和科学家快速构建各种应用所需的所有工具，旨在帮助工程师和科学家解决问题、提高生产力和不断创新。虚拟仪器 LabVIEW 是计算机技术与电子仪器相结合而产生的一种新的仪器模式，它通常是由个人计算机、模块化的功能硬件与用于数据分析、过程通信及图形用户界面的应用软件有机结合构成，使计算机成为一个具有各种测量功能的数字化测量平台。它利用软件在屏幕上生成各种仪器面板，完成对数据的处理、表达、传送、存储、显示等功能。虚拟技术计算机通讯技术和网络技术是信息技术最
5、重要的组成部分。虚拟技术蕴含的巨大潜力使发达国家趋之若鹜，20 世纪 80 年代首先在美国兴起和发展起来的虚拟仪器无疑是虚拟技术领域中的重要组成部分，因此自 1982 年美国研制成功第一台虚拟仪器以来，虚拟仪器在世界范围内发展十分迅速。如世界著名的 NI 公司，已经形成了系列化的虚拟函数信号发生器，信号分析仪，存储示波器，及图表记录仪等产品。进入 90 年代末期，我国一些科研单位及高等院校如清华大学，哈尔滨工业大学，电子科技大学等也十分重视虚拟仪器的开发与研究。虚拟仪器技术经过十几年的发展，而今正沿着总线与驱动程序标准化，软/硬件模块化，编程平台的图形化和硬件模块的即插即用方向进步。以开放式模
6、块化仪器标准为基础的虚拟仪器标准正日趋完善。虚拟仪器技术在发达国家的推广应用也十分普及，不仅在电子测量领域，过程控制领域，包括人们生活的其它许多领域利用虚拟仪器实现复杂的测量与控制系统的例子也很多。虚拟仪器正在继续迅速发展，它可以取代测量技术传统领域的各类仪器。虚拟仪器在组成和改变仪器的功能和技术性能方面具有灵活性和经济性，因而适应于当代科学技术迅速发展和科学研究不断深化所提出的更高更新的测量课题和测量需求。虚拟仪器相比于传统仪器具有诸多优势而这些优势使得虚拟仪器技术非常适用于高等教育实验课程的应用。高等学校特别是理工科学校，教学、科研需要大量的测量分析仪器设备，特别是实验教学，每种仪器都必须
7、配置多套，而且有的仪器设备价格昂贵，因此仪器设备所需投资巨大，一般学校很难满足，造成许多学校仪器设备缺乏和过时陈旧等现象，严重影响教学科研。如果运用虚拟仪器系统，情况就大不一样了。使用虚拟仪器不但可以节约大量仪器设备的经费投入，而且能够提高教学科研的质量与效率。实验教学是许多专业必须进行的一项教学活动。掌握测量仪器和设备的操作使用方法是每个学生进行科学实验基本前提。传统的教学方法是让学生在教师的指导下进行实际的操作使用，随之而来的问题是教师的工作量很大而很难对所有学生进行指导，既影响教学效果又容易造成仪器损坏。运用 LabVIEW辅助实验教学能有效地打到教学目的并且避免仪器的损坏，节约开支。二
8、、主要设计（研究）内容本次毕业设计要求学生熟练掌握 LabVIEW 图形化的编程语言G 语言，并且用该语言实现电子线路中常用信号的采集、产生、处理等设计功能，引用频率调制和相位调制的具体实例，产生波形，对波形进行计算，分别产生调频和调相信号并且显示在面板上。在仪器面板上对载波，调制波，信号幅度，信号频率等参数任意调整，实现动态显示。完成 LabVIEW 在电子线路课程中的应用设计。三、研究方案及工作计划（含工作重点与难点及拟采用的途径）I、 研究方案：下面是本毕业设计的研究方案，主要从工作重点与难点及拟采用的途径来分析。1 重点与难点LabVIEW 程序主要包括两部分：前面板(即人机界面)和方
9、框图程序。前面板用于模拟真实仪器的面板操作，可设置输入数值、观察输出值以及实现图表、文本等显示。框图程序应用图形编程语言编写，相当于传统程序的源代码。其用于传送前面板输入的命令参数到仪器以执行相应的操作。LabVIEW 的强大功能在于层次化结构，用户可以把创建的 VI 程序当作子程序调用，以创建更复杂的程序，而且，调用阶数可以是任意的。LabVIEW 编程方法与传统的程序设计方法不同，它拥有流程图程序设计语言的特点，摆脱了传统程序语言线性结构的束缚。LabVIEW 的执行顺序依方块图间数据的流向决定，而不像一般通用的编程语言逐行执行。在编写方块图程序时，只需从功能模块中选用不同的函数图标，然后
10、再以线条相互连接，即可实现数据的传输。本设计的重点和难点在于用 LabVIEW 实现电子线路常规教学中对典型电路实验的仿真与调试，选取 LabVIEW 在模拟电路和数字电路中应用的实例进行研究，并且给出具体方案。2. 系统软件设计：2.1 LabVIEW在电子线路中运用的实例。基于LabVIEW的频率调制和相位调制频率调制和相位调制是广泛采用的2种基本调制方式。频率调制(frequency modulation,FM)简称调频,它是使载波信号的频率按调制信号规律变化的一种调制方式;相位调制(phase modulation,PM),简称调相,它是使载波信号的相位按调制信号规律变化的一种调制方式
11、。首先根据仪器功能要求,利用虚拟仪器开发平台所提供的子模板,确定程序的流程图、主要处理算法和所实现的技术方法。所用到的数据库(1)数据采集函数库(data acquisition),使用这些函数必须配有数据采集硬件,若只模拟仪器工作原理而不作实际测量,则不必使用。(2)波形函数库(waveform)用于和波形相关的一些操作 ,如波形产生、波形测量、波形文件输入/输出、波形操作、波形显示等。(3)信号处理函数库(signal processing)用于将信号进行一定的变换处理。包括信号产生、时/频域信号分析、相关分析、曲线拟合、滤波器、窗函数等。前面板设计 4 个图形控件来显示波形，4 个数字控
12、件输入参数，一个开关控制运行与停止，2 个字符串输入控件选择调频与调相。在程序前面板输入各个参数值,运行程序,可以清楚看到产生的已调信号及其频谱图,并可通过前面板中的参数控件改变调制信号的幅度,可以看到载波信号的瞬时相位随调制信号的幅度改变而改变;另外可以看到产生已调信号的频谱的改变情况。仪器面板可以对载波、调制波、信号幅度、信号频率等参数可以任意调整,实现动态显示。开始设置参数利用公式产生调幅与调频计算频谱输出已调波形停止？显示已调波显示已调波频谱结束角度调制信号发生器原理框图II、工作计划：起止日期（日/月） 周 次 进度计划2.172.23 1 熟悉课题、收集相关资料2.243.2 2
13、收集、消化相关资料3.33.9 3 拟定设计方案、方案比较3103.16 4 撰写开题报告3.173.23 5 提交毕业设计开题报告，参加开题3.243.31 6 设计方案细化、方案改进4.14.14 7 软件调试4.154.21 8 软件调试、软件设计改进4.224.28 9 撰写设计报告书4.295.5 10 撰写设计报告书5.65.12 11 撰写设计报告书、完成初稿5.135.19 12 设计报告书修订、完成毕业设计5.205.26 13 提交正式设计报告书，参加论文互评5.276.2 14 提交正式设计报告书，参加论文答辩6.36.9 15 设计报告书答辩后修订6.106.16 16
14、 毕业设计完成四、主要参考文献1 刘华君基于 LabVIEW的虚拟仪器设计M北京电子工业出版社，2003.2 尹妍萍，王健，等 LabVIEW在教学测试实验中的应用 J. 实验室研究与探索，2002，21(1)：63-64.3 孙宁，黄惟公基于 LabVIEW与单片机的教学实验系统 J中国仪器仪表，2005(12)：104-107. 4 Gary W.Johnson.LabVIEW图形编程M北京 : 北京大学出版社，2002.5 杨乐平, 李海涛, 肖相生. LabVIEW 程序设计与应用 M北京: 电子工业出版社, 2001.6 海燕，杨建新，郁鼎新，等基于LabVIEW 的虚拟仪器开发 J
15、机械工程师，2000(4)： 33.7 邓焱，王磊 . LabVIEW 7.1 测试技术与仪器应用M北京：机械工业出版社，2004.8 周舒梅动态信号分析及仪器M北京：机械工业出版社，19909 侯国屏,王坤 ,叶齐鑫. LabVIEW 7.1 编程与虚拟仪器设计 M北京：清华大学出版社，2005.10 李刚，林凌 LabVIEW易学易用的计算机图形化编程语言 M北京：北京航空航天大学出版社，2001.11 李字华虚拟仪器开放平台LabVIEW 介绍J计算机自动测量与控制，1996，(3).12 杨乐平, 吕英军.虚拟数字示波器的设计与实现J自动化与仪器表,2000 , (7):28-3.13
16、 何瑛,宋利 ,张伟,等基于LabVIEW 的数据采集卡 (DAQ)驱动程序设计J . 电测与仪表,2000,(4):35-3714 郑利峰, 杨小雪,张汉全基于LabVIEW 频谱分析仪设计 J自动化与仪器仪表,2002(5):4=7115 关旭,张春梅 ,王尚锦.虚拟仪器软件 LabVIEW 和数据采集J 微机发展,2004 ,14(3):77-7916 帕特森 Casmir D Mello,桑德拉D Souza Design and development of a Virtual Instrument for Bio-signal Acquisition and Processing
17、using LabVIEW J.International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering.2013.附录A：英语引文及翻译Design and development of a Virtual Instrument for Bio-signal Acquisition andProcessing using LabVIEWPatterson Casmir DMello1, Sandra DSouza2Department of Instrumenta
18、tion & Control Engineering, M.I.T, Manipal1, 2Sandra.dsouzamanipal.edu1, 2Abstract:The increased performance of personal computers and their reduced cost has made it possible for development of PC based signal processing systems. Hospitals need several measurement systems that can measure physiologi
19、cal parameters of the patients. Although diagnostic medical instruments have been widely used, combining virtual instrument technology to achieve the purpose of physiological measurement has several benefits. These systems are efficient and cost-effective for acquiring and analyzing biomedical signa
20、ls. Utilizing virtual instrumentation to achieve physiological measurement will largely decrease the cost and increase the flexibility of the instruments. This work aims at designing a virtual instrument for acquiring and processing of Electrooculogram signal. Electrooculography (EOG) is a technique
21、 for measuring the resting potential of the retina. Keywords: Data acquisition, signal processing, LabVIEW, Virtual Instrument, EOG measurementI. INTRODUCTIONHospitals need several measurement systems that can measure physiological parameters of the patient. Measurement systems should be able to mea
22、sure accurately the vitals of patient like heart conditions, body temperature, electrical activity of the heart, electrical activity of the brain etc. This information should be readily available to the doctors for diagnosis and proper treatment. PC based signal acquisition, and analysis is an effic
23、ient and cost effective method for biomedical signal acquisition and monitoring. Isolation of the subject from the electronic circuitry is very important. Also, since the bio signal level is very low, amplification of signals is important. Hence, a PC based system consists of additional circuits for
24、 isolation and amplification of the signals. Combining virtual instrumentation technology for physiological measurements is an upcoming technology that is currently rising up at a faster rate. The cost can be drastically brought down and the flexibility can be increased by use of virtual instrumenta
25、tion .National Instruments LabVIEW is a platform and development environment for a visual programming. The purpose of such programming is automating the usage of processing and measuring equipment in any laboratory setup. Controls and indicators on the front panel allow an operator to input data int
26、o or extract data from a running virtual instrument. A key benefit of LabVIEW over other development environments is the extensive support for accessing instrumentation hardware. The paper is organized as follows: Section I, gives introduction to virtual instrumentation and need of the current work,
27、 Section II, explains the bio signal details, Section III discusses the challenges in the design, Section IV explains the performance and results, and the last Section V concludes the paper followed by references used.II. BIOELECTRIC SIGNAL-.ELECTOOCULOGRAMElectric potentials are generated as a resu
28、lt of movement of the eyeballs within the conductive environment of the skull. Electrodes placed on either side of the eyes or above and below them pick up the potentials generated by the motion of the eyeball. This potential varies approximately in proportion to the movement of the eyeballs. This s
29、ignal is small separately. This requires five electrodes which are placed above and below the eye for vertical movements, and on the sides of the eye (canthi) for horizontal movements. A reference electrode is placed on the forehead of the subject. Considering the cost and reliability makes Silver (
30、Ag)-Silver Chloride (AgCl) electrodes ideal for EOG. An electrolytic gel based on sodium chloride is applied to the skin since the upper layers of the skin are poor conductors of electricity. Several methods have been proposed in literature that use Electrooculograms (EOGs) occurring as a result of
31、eye movements 3-5. An electric wheelchair controlled by eye movements using EOG has been developed as a movement support device. An EOG based hospital alarm system has been successfully tested. An eye gazing system for detecting any point where the eye gazes on the screen has been developed for comm
32、unication assistance purposes 4, 5。Noise ReductionEOG signals have a range of 0.5Hz to 30Hz. Thus, a low pass filter with 30Hz cutoff could remove most of the high frequency noises. And a high pass filter of 0.5 Hz is required, which together form a band pass of 50 Hz. Other noise artifacts are most
33、ly transients caused, for example, by the turning of an electrical switch on/off in the vicinity of the electrodes, contraction of the facial or neck muscles, slippage of the electrode due to sweat and eye blinking .However, the signals produced by eye blinks are, in fact, quite regular. They appear
34、 as sudden spikes with distinguishing amplitudes. Hence it is possible to easily recognize. Changed when the eye is moved and the movement of the eye is translated into electrical change of potential. This potential can be noninvasively recorded by using surface electrodes.，provides an on invasive m
35、ethod for recording full range of eye movements. The resting potential is A pair of electrodes is required for measuring the resting potential of the retina. It Hz). Electrooculography is a technique for (10 to 100microV) and has low frequencies (dc to 30)III.CONSTRUCTION AND CHALLENGESThe main obje
36、ctive of the current work carried on is to develop a virtual instrument which can acquire the EOG signal, perform noise elimination and amplification. Acquiring the signal using NI DAQ, designing the suitable low cost amplifier for amplification and designing of low pass and high pass filters was do
37、ne. The acquired signal was displayed using LabVIEW front panel. The front panel and block diagram have been designed. The basic block diagram is shown is fig 1. filter of bandwidth 0.5Hz to 30 Hz. Power line frequency can be easily removed, using a notch filter Protection circuit: This circuit incl
38、udes protection devices so that the high voltages that may appear across the input to the electrooculography under certain conditions do not damage it. Preamplifier: The input preamplifier stage carries out the initial amplification of the EOG. This stage should have very high input impedance and a
39、highCommon-ode-rejection ratio (CMRR). Isolation circuit: The circuitry of this block contains a barrier to the passage of current from the power line (50 Hz). This barrier would prevent dangerous currents from flowing from the patient through the amplifier to the ground of the recorder or Microcomp
40、uter. Driver amplifier: Circuitry in this block amplifies the EOG to a level at which it can appropriately record the signal on the recorder. This stage also carries out the band pass filtering of the electrocardiograph to give the frequency characteristics of the signal. A. Signal Acquisition and p
41、rocessing Data acquisition cards for multiple channels for analog input and outputs are available. Using the libraries, programs for the data acquisition are quickly and easily made. Additional noise is filtered using the choice of filters like Butterworth, Bessel, Chebyshev I, and Chebyshev II prov
42、ided in the LabVIEW software. The installation of the DAQ card includes:1. Installation of the application software 2. Installation of the DAQ card driver first, before assembling DAQ card into the desk top computer. This process can ensure WINDOWS to detect the DAQ card.3. Installing the necessary
43、devices, accessories and cables. 4. Power on the computer. 5. Confirm that the device is recognized. 6. Run the test Panel. In the current work, M Series USB-6221 is used as data acquisition interface.B. Design of front panel Different blocks used in the front panel are:1. Case structure: Only one s
44、ubdiagram is visible at a time, and the structure executes only one case at a time. An input value determines which subdiagram executes. 2. Time delay: The Wait (ms) function waits until the millisecond counter counts to an amount equal to the input you specify. This function guarantees that the loo
45、p execution rate is at least the amount of the input you specify. 3. Filter: The Filter Express VI processes a signal through filters and windows. Filters used include the following: High pass, Low pass, Band pass, Band stop, and Smoothing. Windows used include Butterworth, Chebyshev, Inverse Chebys
46、hev, Elliptical, and Bessel.4. Waveform graph: The waveform graph displays one or more plots of evenly sampled measurements.5. Amplitude and level measurements: he Amplitude and Level Measurements Express VI performs voltage measurements on a signal. These include DC, rms, maximum peak, minimum peak
47、, peak to peak, cycle average, and cycle rms measurements.6. Tone measurements: The Tone Measurements Express VI searches for a single tone with the highest frequency or highest amplitude. It also finds the frequency and amplitude of a single tone. 7. Write to measurement file:The Write to Measureme
48、nt File Express VI writes a file in LVM or TDM file format. 8. Build table: Converts a signal or signals into a table of data that lists the amplitude of each signal and the time data for each point in the signal.9. Result table: Use the table control to create a table on the front panel. Each cell
49、in a table is a string, and each cell resides in a column and a row. Therefore, a table is a display for a 2D array of strings.10. String: A string is a sequence of displayable or non-displayable ASCII characters. Strings provide a platform independent format for information and data.11. While loop: Repeats the sub-diagram inside it until the conditional termin
