外文翻译--波形发生器的进展.doc

波形发生器的进展波形发生器是能够产生大量的标准信号和用户定义信号，并保证高精度、高稳定性、可重复性和易操作性的电子仪器。函数波形发生器具有连续的相位变换、和频率稳定性等优点，不仅可以模拟各种复杂信号，还可对频率、幅值、相移、波形进行动态、及时的控制，并能够与其它仪器进行通讯，组成自动测试系统，因此被广泛用于自动控制系统、震动激励、通讯和仪器仪表领域。早在20年代，当电子设备刚出现时，他就出现了。随着通信和雷达技术的发展，40年代出现了主要用于测试各种接收机的标准信号发生器，使信号发生器从定性分析的测试仪器成为定量分析的测量仪器。同时还出现了可用来测试脉冲电路或用作脉冲调试器的脉冲信号发生器。由于早期的信号发生器的机械结构比较复杂，功率比较大，电路比较简单，（与数字仪器，示波器相比），因此发展比较缓慢。直到1964年才出现了第一台全晶体管的信号发生器。自60年代以来，信号发生器有了迅速的发展，出现了函数发生器、扫频信号发生器、合成信号发生器、程控信号发生器等新种类。各类信号发生器的性能指标也有了大幅度的提高，同时在简化机械结构、小型化、多功能等各方面也有了显著的发展。在70年代前，信号发生器主要有两类：正弦波和脉冲波，而函数发生器介于两类之间，能够提供正弦波、余弦波、方波、三角波、上弦波等几种常用标准波形，产生其它波形时，需要采用较复杂的电路和机电结合的方法。这个时期的波形发生器多采用模拟电子技术，而且模拟器件构成的电路存在着尺寸大、价格贵、功耗大等缺点，并且要产生较为复杂的信号波形，则电路结构非常复杂。同时，主要表现为两个突出问题，一是通过电位器的调节来实现输出频率的调节，因此很难将频率调到某一固定值；二是脉冲的占空比不可调节。在70年代后，微处理器的出现，可以利用处理器、A/D/和D/A，硬件和软件使波形发生器的功能扩大，产生更加复杂的波形。这时期的波形发生器多以软件为主，实质是采用微处理器对DAC的程序控制，就可以得到各种简单的波形。90年代末，出现几种真正高性能、高价格的函数发生器、但是HP公司推出了型号为HP770S的信号模拟装置系统，它由HP8770A任意波形数字化和HP1776A波形发生软件组成。HP8770A实际上也只能产生8中波形，而且价格昂贵。不久以后，Analogic公司推出了型号为Data-2020的多波形合成器，Lecroy公司生产的型号为9100的任意波形发生器等。到了二十一世纪，随着集成电路技术的高速发展，出现了多种工作频率可过GHz的DDS芯片，同时也推动了函数波形发生器的发展，2003年，Agilent的产品33220A能够产生17种波形，最高频率可达到20M，2005年的产品N6030A能够产生高达500MHz的频率，采样的频率可达1.25GHz。由上面的产品可以看出，函数波形发生器发展很快近几年来，国际上波形发生器技术发展主要体现在以下几个方面： （1）过去由于频率很低应用的范围比较狭小，输出波形频率的提高，使得波形发生器能应用于越来越广的领域。波形发生器软件的开发正使波形数据的输入变得更加方便和容易。波形发生器通常允许用一系列的点、直线和固定的函数段把波形数据存入存储器。同时可以利用一种强有力的数学方程输入方式，复杂的波形可以由几个比较简单的公式复合成v=f(t)形式的波形方程的数学表达式产生。从而促进了函数波形发生器向任意波形发生器的发展，各种计算机语言的飞速发展也对任意波形发生器软件技术起到了推动作用。目前可以利用可视化编程语言(如Visual Basic, Visual C等等)编写任意波形发生器的软面板，这样允许从计算机显示屏上输入任意波形，来实现波形的输入。（2）与VXI资源结合。目前，波形发生器由独立的台式仪器和适用于个人计算机的插卡以及新近开发的VXI模块。由于VXI总线的逐渐成熟和对测量仪器的高要求，在很多领域需要使用VXI系统测量产生复杂的波形，VXI的系统资源提供了明显的优越性，但由于开发VXI模块的周期长，而且需要专门的VXI机箱的配套使用，使得波形发生器VXI模块仅限于航空、军事及国防等大型领域。在民用方面，VXI模块远远不如台式仪器更为方便。（3）随着信息技术蓬勃发展，台式仪器在走了一段下坡路之后，又重新繁荣起来。不过现在新的台式仪器的形态，和几年前的己有很大的不同。这些新一代台式仪器具有多种特性，可以执行多种功能。而且外形尺寸与价格，都比过去的类似产品减少了一半。早在1978年，由美国Wavetek公司和日本东亚电波工业公司公布了最高取样频率为5MHz，可以形成256点(存储长度)波形数据，垂直分辨率为8bit，主要用于振动、医疗、材料等领域的第一代高性能信号源，经过将近30年的发展，伴随着电子元器件、电路、及生产设备的高速化、高集成化，波形发生器的性能有了飞速的提高。变得操作越来越简单而输出波形的能力越来越强。波形操作方法的好坏，是由波形发生器控制软件质量保证的，编辑功能增加的越多，波形形成的操作性越好。波形发生器是信号源的一种，主要给被测电路提供所需要的己知信号(各种波形)，然后用其它仪表测量感兴趣的参数。可见信号源在各种实验应用和试验测试处理中，它的应用非常广泛。它不是测量仪器，而是根据使用者的要求，作为激励源，仿真各种测试信号，提供给被测电路，以满足测量或各种实际需要。目前我国己经开始研制波形发生器，并取得了可喜的成果。但总的来说，我国波形发生器还没有形成真正的产业。就目前国内的成熟产品来看，多为一些PC仪器插卡，独立的仪器和VXI系统的模块很少，并且我国目前在波形发生器的种类和性能都与国外同类产品存在较大的差距，因此加紧对这类产品的研制显得迫在眉睫。THE DESIGN OF ARBITRARY WAVEFORM GENERATORSThe profile generator is can produce the massive standard signals and the user definition signal, and guarantees the high accuracy, high stable, the repeatability and the easy operational electronic instrumentation.The function profile generator has the continual phase transformation, and merits and so on frequency stability, not only may simulate each kind of complex signal, but also may to the frequency, the peak-to-peak value, the phase-shift, the profile carry on the tendency, the prompt control, and can carry on the communication with other instruments, the composition automated test system, therefore widely uses in the automatic control system, the vibration drive, the communication and the instrument measuring appliance domain.As early as in 20s, when the electronic installation just appeared, he appeared.Along with the correspondence and the radar technology development, the 40s appeared has mainly used in testing each kind of receiver the standard signal generating device, caused the signal generating device to become the quantitative analysis from the qualitative analysis measuring instrument the metering equipment.Simultaneously also appeared available has tested the pulse electric circuit or serves as the pulse debugger the pulse signal generating device.Quite is complex as a result of the early signal generating device mechanism, the power quite is big, the electric circuit quite is simple, (with digital instrument, oscilloscope compares), therefore develops quite slowly.Only then appeared the first holocrystalline tube signal generating device until 1964. Since the 60s, the signal generating device had the rapid development, appeared the function generator, has swept the frequency signal generating device, the composite signal generator, the program control signal generating device and so on the new type.Each kind of signal generating device performance index also had the large scale enhancement, simultaneously in the simplification mechanism, the miniaturization, multi-purpose and so on various aspects also had the remarkable development. Before the 70s, the signal generating device mainly has two kinds: Sine wave and pulse wave, but the function generator is situated between between two kinds, can provide the sine wave, the cosine wave, the square-wave, the triangular wave, the top chord wave and so on several kind of commonly used standard wave patterns, when has other profiles, needs to use the complex electric circuit and the mechanical and electrical union method.This time profile generator uses the simulation electronic technology, moreover simulates the electric circuit which the component constitutes to have the size in a big way, the price expensive, the power loss big and so on the shortcomings, and must have the more complex waveform, then the electric circuit structure is extremely complex.At the same time, the main performance is two prominent questions, one is realizes the output frequency adjustment through the potentiometer adjustment, therefore adjusts very difficultly the frequency some fixture; Two is the pulse dutyfactor cannot adjust. After the 70s, the microprocessor appearance, may use the processor, A/D/and D/A, the hardware and the software causes the profile generator the function expansion, has a more complex profile.This time profile generator many by software primarily, the essence is uses the microprocessor to the DAC procedure control, may obtain each kind of simple profile. But at the end of the 90s, appeared several kind of true high performances, the high price function generators, HP Corporation has promoted the model is the HP770S signal imitation installment systems, it had the software by the HP8770A random profile digitization and the HP1776A profile to be composed.HP8770A in fact also only can have 8 profiles, moreover the price is expensive.Soon after, Analogic Corporation has promoted the model is the Data-2020 multi-profile synthesizer, the model which Lecroy Corporation produces is 9100 random profile generators and so on.To the 21st century, along with the integrated circuit technology high speed development, appeared many kinds of operating frequency to be possible the GHz DDS chip, simultaneously also impelled the function profile generator development, in 2003, Agilent product 33220A could have 17 kind of profiles, the upper frequency may achieve 20M,2005 the year product N6030A could produce reaches as high as the 500MHz frequency, the sampling frequency may reach 1.25GHz.May see by above product, function profile generator development very quick in the last few years, on the international profile generator technological development mainly manifests in following several aspects: (1) quite was in the past narrow and small as a result of the frequency very low application scope, the output wave shape frequency enhancement, enabled the profile generator to apply in the more and more broad domain.The profile generator software development is causing the profile data the input to become even more is more convenient and is easy.The profile generator usual permission with a series of spots, the straight line and the fixed function section stores the profile data the memory.Simultaneously may use one powerful mathematics equation input way, the complex profile may compound become the v=f(t) form by several quite simple formulas the profile equation mathematical expression production.Thus promoted the function profile generator to the random profile generator development, each kind of machine language rapid development also played to the random profile generator software technology the impetus role.At present may use the visualization programming language (for example Visual Basic, Visual C and so on) compiles the random profile generator the soft kneading board, like this allows from the computer display monitor to input the random profile, realizes the profile input. (2) and VXI resources union.At present, the profile generator and is suitable by the independent table model instrument for the personal computer VXI module which inserted the card as well as recently develops.Because VXI main line gradually mature and to metering equipment high request, needs to use VXI system survey in very many domains to have the complex profile, VXI system resources have provided the obvious superiority, but because develops VXI module the cycle to be long, moreover needs the special VXI engine case the necessary use, causes the profile generator VXI module only to be restricted in the aviation, the military and the national defense and so on the large-scale domain.In the civil aspect, VXI module was inferior by far the table model instrument is more convenient. (3) along with the information technology vigorous development, the table model instrument after walked section of downhill, prospers.But the present new table model instrument shape, has the very big difference with several year ago oneself.These new generation of table model instrument has many kinds of characteristics, may carry out many kinds of functions.Moreover the external dimensions and the price, all reduced compared to the past similar product one half. As early as in 1978, will announce the highest sampling frequency by American Wavetek Corporation and Japanese East Asia Electric wave Industrial corporation is 5MHz, may form 256 (memory length) the profile data, the vertical resolution is 8bit, mainly uses in vibrating, domain and so on medical service, material first generation of high performance supply oscillators, will pass through is near 30 years development, was following the electronic primary device, the electric circuit, and the production equipment high speed, Gaoji Cheng Hua, the profile generator performance had the rapid enhancement.More and more becomes the operation to be simple output wave shape ability to be more and more strong.The profile operating procedure quality, is by the profile generator control software quality assurance, the edition function increases more much, the profile forms operationally better. The profile generator is the su