信息工程-通信-外文翻译-外文文献-英文文献-基于虚拟仪器的信号发生器的设计与实现.doc

原 文1、虚拟仪器的产生背景当今我们处于一个正在高度发展的信息社会，要求在有限的时空上实现大量信息的交换，必然带来信息密度的急剧增大，要求电子系统对于信息的处理速度越来越高，功能越来越强，这使得系统结构日趋复杂。一方面电子技术及市场的发展从客观上要求测试仪器向自动化及柔性化的方向发展，另一方面，电子技术及市场的发展也给虚拟仪器的产生提供了可能。在这种形式下，基于微计算机的虚拟仪器逐步变得现实，它的出现和广泛使用为测试系统的设计提供一个极佳的模式，并且使工程师们在测量和控制方面得到强大功能和灵活性。2虚拟仪器的概念虚拟仪器(Virtual Instrument，简称VI)的概念是由美国国家仪器公司(NI)在20世纪80年代最早提出的。虚拟仪器就是在以通用计算机为核心的硬件平台上，由用户设计定义、具有虚拟前面板、测试功能由测试软件实现的一种计算机仪器系统。其核心的思想是利用计算机的强大资源使本来需要硬件实现的技术软件化，以便最大限度地降低系统成本，增强系统功能与灵活性。虚拟仪器代表着从传统硬件为主的测试系统到以软件为中心的测试系统的根本性转变。虚拟仪器的出现是仪器发展史上的一场革命，代表着仪器发展的最新方向和潮流，对科学技术的发展和工业生产的进步将产生不可估量的影响。虚拟仪器具有性能高、扩展性强、开发时间短、无缝集成等优势。3. 图形化虚拟仪器开发平台LABVIEW 简介及其优势LABVIEW是Laboratory Virtual Instrument Engineering Workbench (实验室虚拟仪器集成开发环境)的简称，是由美国国家仪器公司(National instruments, IN)创立的一个功能强大而又灵活的仪器和分析应用开发工具。Labview一种图形化的编程语言，主要用来开发数据采集，仪器控制及数据处理分析等软件，功能强大。目前，该开发软件在国际测试、测控行业比较流行，在国内的测控领域也得到广泛应用。函数信号发生器是在科学研究和工程设计中广泛应用的一种通用仪器。LABVIEW软件开发平台具有以下优点: 1、图形化的编程方式，设计者无需写任何文本格式的代码，是真正的工程师的语言。2、提供了丰富的数据采集、分析及存储的库函数。3、既提供了传统的程序调试手段，如设置断点、单步运行，同时提供有独到的高亮执行工具，使程序动画式运行，利于设计者观察程序运行的细节，使程序的调试和开发更为便捷。4、32bit的编译器编译生成32bit的编译程序，保证用户数据采集、测试和测量方案的高速执行。5、囊括了DAQ, GPIB, PXI, VXI, RS-232/485在内的各种仪器通信总线标准的所有功能函数，使得不懂总线标准的开发者也能够驱动不同总线标准接口设备与仪器。6、提供大量与外部代码或软件进行连接的机制，诸如DLL(动态连接库)、DDE(共享库)、ActiveX等。7、强大的Internet功能，支持常用网络协议，方便网络、远程测控仪器的开发。 图形化程序设计编程简单、直观、开发效率高。随着虚拟仪器技术的不断发展，图形化的编程语言必将成为测试和控制领域内最流行的发展趋势。4. 虚拟仪器的发展方向虚拟仪器作为新兴的仪器仪表，其优势在于用户可自行定义仪器的功能和结构等，且构建容易、转换灵活，它已广泛应用于电子测量、声学分析、故障诊断、航天航空、机械工程、建筑工程、铁路交通、生物医疗、教学及科研等诸多方面。随着计算机软硬件技术、通信技术及网络技术的发展，给虚拟仪器的发展提供了广阔的天地，国内外仪器界正看中这个大市场。测控仪器将会向高效、高速、高精度和高可靠性以及自动化、智能化和网络化的方向发展。开放式数据采集标准将使虚拟仪器走上标准化、通用化、系列化和模块化的道路。虚拟仪器作为教学的新手段，已慢慢地走进了电子技术的课堂和实验室，正逐渐改变着电子技术教学的传统模式，这也是现代教育技术发展的必然。在电工电子实验室的建设中，实验室常规设备有的已经老化，有的技术上有些落后，在当前学校经费较少的情况下，如果配置常规仪器、仪表，学校财力难以支付，也不符合目前学校的实际。而且，随着测试仪器的数字化、计算机化的发展趋势，传统测试仪器渐渐有被取代的趋势。如果运用虚拟仪器技术，以微机为基础，构建集成化测试平台，代替常规仪器、仪表，不但满足电工电子实验教学的需要，而且将这批微机可作为其他有关计算机课程教学用机，大大提高了设备利用率，降低了实验室建设的成本。当前应该解决的是如何使虚拟仪器和现有仪器配合，挖掘现有仪器的潜力，达到逐步淘汰和取代传统仪器的目的。总之，虚拟仪器有很广阔的发展空间，并最终要取代大量的传统仪器成为仪器领域的主流产品，成为测量、分析、控制、自动化仪表的核心。5.信号发生器概述信号发生器(signal generator)又称信号源或振荡器，是一种能提供各种频率、波形和输出电平电信号，常用作测试的信号源或激励源的设备。在生产实践和科技领域中有着广泛的应用。随着现代电子、计算机和信号处理等技术的发展，极大促进了数字化技术在电子测量仪器中的应用，使原有的模拟信号处理逐步被数字信号处理所代替，从而扩充了仪器信号的处理能力，提高了信号测量的准确度、精度和变换速度，克服了模拟信号处理的诸多缺点，数字信号发生器随之发展起来。传统的信号发生器其功能完全靠硬件实现，功能单一而且用户的购置、维护费用高。更重要的是，对于传统的信号发生器，其功能一旦确定便不能更改，用户要想使用新的功能则必须重新购买新的仪器，传统信号发生器的不足是显而易见的。虚拟仪器是将仪器技术、计算机技术、总线技术和软件技术紧密的融合在一起，利用计算机强大的数字处理能力实现仪器的大部分功能，打破了传统仪器的框架，形成的一种新的仪器模式。译 文1、The generation background of virtual instrumentToday we are in a highly developed information society, which require a limited time and space to achieve a large  amount of information exchange, inevitably bring about the rapid increase of information density，required the electronic systems have a faster speed and more powerful function for information processing. On the one hand the development of electronic technology and market requirements objectively make the test instrument develop to the direction of automation and flexible, On the other hand, the electronic technology and market development also make virtual instrument possible. In this situation, the virtual instruments based on micro-computer gradually become a reality, its appearance and extensively use provide an excellent model for the design of test system and allows engineers more powerful and flexible in measure and control.2 、The concept of virtual instrumentVirtual Instruments (Virtual Instrument, referred to as VI) concept is first proposed by the National Instruments (NI) in 1980s' . The virtual instrument is a kind of Computer equipment system which based on the general purpose computer as the core hardware platform, defined by the user with a virtual front panel, the test function is performed by a computer testing software. The core idea is to use a powerful computer resources that would otherwise require hardware to software of the technology in order to minimize system cost, enhance system functionality and flexibility. The virtual instrument represents the fundamental changes from traditional hardware-based test system to Software-centric test system. The emergence of virtual instrument is a revolution in the history of instruments, it represents the latest development direction and trend of instrument, produced an immeasurable influence on the development of science and technology and industrial production progress. Virtual instrument have many advantages, such as high performance, scalability, strong, development time is short and seamless integration.3、graphical virtual instrument development platform-LABVIEW introduction and its advantages LABVIEW is short for Laboratory Virtual Instrument Engineering Workbench, it is a powerful and flexible instrumentation and analysis of application development tool created by National Instruments (National instruments, IN) 。Labview is a graphical programming language, mainly used to develop data acquisition, instrument control and data processing and analysis software. Currently, the development of software is popular in the international test, measurement and control industry , measurement and control areas in the country has also been widely used. Function Generator is a generic instrument widely used in scientific research and engineering design。LABVIEW software development platform has the following advantages：1. It use graphical programming approach, the designer do not need to write any code in text format, It is the true language of engineers.2. It provides a wealth of data collection, analysis and storage of the library functions.3. Provides both the traditional debugging tools, such as setting breakpoints, single step, while providing a unique tool for highlighting the implementation of that program to run the animation style, which will help designers to observe the details of running, so that debugging and development of more is convenient.4. The 32bit compiler generates 32bits compiled program to ensure that user data acquisition, test and measurement solutions for high-speed implementation.5. Include the functions of the communication bus in DAQ, GPIB, PXI, VXI, RS-232/485 and other kind of equipment, making the developer who do not know the different bus stand can driver the interface devices and instruments 6. Provide a substantial amount of code or software for connecting external mechanisms, such as DLL (dynamic link library), DDE (shared libraries), ActiveX and so on.7. Powerful Internet capabilities, support for common network protocols to facilitate networking , remote monitoring and control equipment development.Graphical program programming is simple and intuitive, the development and high efficiency. With the continuous development of virtual instrumentation and graphical programming language, test and control areas will become the most popular trends.4、The development direction of virtual instrument As a new instruments, the advantage of the virtual instruments is that user-defined functions and structure of the instrument, and easy to build, Conversion flexible it has been widely used in electronic measurement, acoustic analysis, fault diagnosis, aerospace, mechanical engineering, construction Engineering, railway transportation, biomedical, and many other aspects of teaching and research. With the development of computer hardware and software technology, communications technology and network technology, providing a vast world of the development of the virtual instrument, Chinese and foreign equipment sector is the large market. Monitoring equipment will be the efficient, high-speed, high precision and high reliability, and automation, intelligence and network direction. Open standards for data collection will put instrument on a standardized, universal, serial and modular way. The virtual instrument as a new teaching tool, has been slowly walked into the classroom and laboratory and is gradually changing the traditional mode of electronic technology teaching, which is the inevitable development of modern educational technology. In the construction of electric and electronic laboratory, some laboratory equipment have been conventional aging, some have technical backward, in the current school funds under the circumstances of less, If buy regular instrument and meter, it is difficult for the school to pay for it and it is not fit with the schools situation. Moreover, with the test equipment digitalized, computerized trend, the traditional test instruments have the trend been gradually replaced. If the virtual instrument technology, computer-based, building integrated test platform, instead of conventional instruments , meters, not only to meet the needs of electrical and electronic experimental teaching, and will these computer courses on computer can be used as teaching other machines , greatly improving Equipment utilization, reducing the cost of laboratory construction. The current should be addressed is how to make virtual instruments and existing instruments together, and tap the potential of existing equipment, to phase out and replace the traditional instrumentation . In short, the virtual instrument has a broad space for development, and ultimately to replace the large number of traditional instruments into the mainstream of the field instrumentation products, as measurement, analysis, control, automation instrument core.5、 Signal Generator OverviewSignal generator (signal generator), also known as signal source or oscillator, is a kind of equipment to provide a variety of frequency, waveform, and output level signal, the signal source used for testing or excitation. It has been widely used in the science and technology and production practice. With the development of modern electronics, computers and signal processing technology, Advancing digital technology in the application of electronic measuring instruments, so that the original analog signal processing gradually being replaced by digital signal processing to expand the instrument signal processing Capacity, improved signal measurement accuracy , precision and speed of change to overcome the many shortcomings of analog signal processing, digital signal generators were developed together. The functions of traditional signal generators are carried out solely on hardware, and at the same time the functions of traditional signal generators are singleness and costly for purchasing and maintaining, What is more important is that the functions of traditional signal generators can not be altered once they are fixed. Users must get new ones so long as they want new functions. Thus, the defects of traditional signal generators are obvious. Virtual instrument is the instrument technology, computer technology, bus technology and software technology closer together, the use of powerful digital computer processing power to achieve most of the functions the instrument, breaking the traditional instruments of the framework, the formation of a new instrument model .