中英文翻译_彭程

1、Circuitmake our life better Electrical engineering is an exciting and challenging profession for anyone who has a genuine interest in,and aptitude for,applied science and mathematics.Over the past century and a half,electrical engineers have played a dominant role in the development of systems that

2、have changed the way people live and work.Satellite communication links ,telephones ,digital computer,televisions,diagnostic and surgical medical equipment, assembly-line robots,and electrical power tools are unrepresentative components of systems that define a modern technological socierty.As an el

3、ectrical engineer,you can participate in this ongoing technological revolution by improving and refining these exsisting systems and by discovering and developing new systems to meet the needs of our ever-changing socierty. Now let's simply come to understand the content of electrical engineerin

4、g in order to make our have a better understanding to the topic of this article “Circuit make our life better”.Finally, we introduce the methods of modern circuit design.1. Electrical Engineering:An OverviewElectrical engineering is the profession concerned with systems that produce,transmit,and mea

5、sure electric sigals.Electrical engineering combines the physicists model of natural phenomena with the mathematicians tools for manipulating those models to produce systems that meet practical needs.Electrical systems pervade our ves lives ;they are found in homes,schools, workplaces ,and transport

6、ation vehicles everywhere.We begin by presenting a few examples from each of the five major classifications of electrical systems: communication systems computer systems control systems signal processing systemsThen we describe how electrical engineers analyze and design such systems.Communion syste

7、ms are electrical systems that generate,transmit ,and distribute information.Well-known examples include television equipment ,such as cameras,transmitters, receivers, and VCRs; radio telescopes, used to explore theuniverse;satellite systems ,which return images of other Planets and our own;rada ssy

8、stems,used to coordinate plane flight;and telephone systems.Figure 1 A telephone systemsFigure 1depicts the major components of a modern telephone system.Starting at the left of the figure,inside a telephone,a microphone turns sound waves into electrical sigals.These sigals are carried to a switchin

9、g center where they are combined with the sigals from tens,hundreds or thousands of other telephones.The combined signals leave the switching center;their form depends on the distance they must trave. In our example, they are sent through wires in underground coaxial cables to a microwave transmissi

10、on station.Here,the signals are transformed into microwave frequencies and broadcast from a transmission antenna through air and space, via a communication satellite,to a reciving antenna.The microwave receiving station translates the microwave signals into a form suitable for further transmission,p

11、erhaps as pulses of light to be sent through fiber-optic cables. On arriving at the second switching center,the combined signals are separated,and each is routed to the appropriate telephone,where an earphone acts as a speaker to convert their received electric signals back into sound wave.Imagine t

12、he challenge involved indesigning,building,and operating each circuit in a way that guarantee that all of the hundreds of thousands of simultaneous calls have high-quality connections.Computer systems use electric signals to process information ranging from word processing to mathematician computati

13、ons.Systems range in size and power from pocket calculators to personal computers to supercomputers that perform such complex tasks as processing weather data and modeling chemical interactions of complex organic molecules. These systems include network of microcircuits, or integrated circuits-posta

14、ge-stampsized assemblies of hundreds,thousands,or millions of elecrical components that ofen operate at speeds and power levels close to fundamental physical limits,including the speed of light and the thermodynamic law.Control systems use electric signals to regulate processes. Examples include the

15、 control of temperatures,pressures, and flow rates in an oil refinery; the fuel-air mixture in a fuel-injected automobile engine;mechanisms such as the motors,doors, and lights in elevators;and the locks in the Panama Canal.The autopilot and autolanding systems that help to fly and land airplanes ar

16、e also familiar control systems.Power systems generate and distribute electric power.Electric power, which is the foundation of our technology-based society,usually is generated in large quantities by nuclear,hydroelectric,and thermal(coal-,oil-,or ags-fired)generators. Power is distributed by a gri

17、d of conductors that crisscross the country.A major challenge in designing and operating such a system is to provide sufficient redundancy and control so that failure or any piece of equipment does not leave a city,state,or region completely without power.Signal-processing systems act on electric si

18、gnals that represent information. They transform the signals and information contained in them into a more suitable form.There are many different ways to process the signals their information.For example,imagine-processing systems gather massive quantities of data from orbiting weather satellites, r

19、educe the amount of data to a manageable levels, transform the remaining data into a video imagine for the evening news broadcast.A computerized tomography(CT)scan is another example of an imagine-processing system. It takes signals generated by a special X-ray machine and transform them into an ima

20、ge suchas the one in Fig. 2.Although the original X-ray signals are of little use to a physician,once they are processed into a recognizable image the information they contain can be used in the diagnosis of diseas and injury.Figure 2 CT A scan of an adult headConsiderable interaction takes place am

21、ong the engineering disciplines involved in designing and operating these five classes of systems.Thus communication engineers use digital computers to control the flow of information.Computers contain control systems and control systems contain computers. Power systems require extensive communicati

22、ons systems to coordinate safely and reliably the operation of components,which may be spread across a continent.A signal-processing system may involve a communication link,a computer,and a control system.Although elecrical engineers may be interested primarily in one area, they must also be knowled

23、geable in other areas that interact with this area of interest.This interaction is part of what makes elecrical engineering a challenging and exciting profession.The emphasis in engineering is on making things work,so an engineer is free to acquire and use any technique,from any field,that helps to

24、get the job done.2. the methods of modern circuit designIn a field as diverse as elecrical engineering,you might well ask whether all of its branches have anything in common.The answer is yes-electric circuits.An electric circuit is a mathematical model that approximates the behavior of an actual el

25、ectric system.As such,it provide an important foundation for learning the details of how todesign and operate systems such as those just described.The models, the mathematical techniques,and the language of circuit theory will form the intellectual framework for your future engineering endeavors.As

26、a practicing engineer,you will not be asked to solve problems that have already been solved.Wheter you are trying to improve the perfomance of an existing system or creating a new system,you will be working on unsolved problems. Some general problem-solving procedures are presented here.Many of them

27、 pertain to thiking about and organizing your solutions strategy before proceeding with calculations. Identify whats given and whats to be found.In problem solving,youneed to know your destination before you can select a route for getting there. What is the problem asking you to solve or find?Someti

28、mes the goal of the problem is obvious;other times you may need to paraphrase or make lists or tables of known and unknown information to see your objective. Sketch a circuit diagram or other visual models. Translating a verbalproblem description into a visual model is often a useful step in the sol

29、ution processed. If a circuit diagram is already provided,you may need to add information into it,such as lables,values,or reference directions. You may also want to redraw the circuit in a simpler,but equivalent,form. Think of several solution methods and decide on a way of choosingamong them .Ther

30、e are many analytical tools in practic, several of which may work on a problem. But one method may produce fewer equations to be solved than another,or it may require only algebra instead of calculus to reach a solution. Such efficiencies,if you can anticipate them,can stre- amline your calculations

31、 considerably.Having an alternative methond in mind also gives you a path to pursue if your first solution attempt bogs down. Use your creativity.If you suspect that your anwser is off base or if thecalculations see to go on and on without moving toward a solution,you should pause and consider alter

32、natives.You may need to revisit your assumptions or select a different solution method.Or, you may need to takea less-conventional proproblem-solving approch, such as working backward a solution. Test your solution. Ask yourself whether the solution youve obtainedmakes sense.Does the magnitude of th

33、e answers seem reasonable?Is the solution physically realizable?You want to go further and rework the problem via an alternative method. Doing so will not only test the validity of your original answer,but will also help develop your intuition about the most efficient solution methods for various ki

34、nds of problems. In the real world,safety critical designs are always checked by several independent means.Getting into the habit of checking your answers will benefit you as a student and as a practicing engineer.Thus, this article focuses on the circuit applicatons in real life to draw readers att

35、enton on the circuit. And later we introduce the general method of circuit design,attempting to help those who have interest in circuit designing. Of course if you want to really enjoy the joy of circuit designing you must act.电 路使我们的生活更加方便舒适 对于喜爱应用科学和数学方面并有这方面才华的人来说，电气工程是一个令人着迷并且具有挑战性的领域。在过去的一个半世纪里

36、，电气工程师已经在推动系统的发展进步和改变人们的生活工作方式上扮演了重要而又突出的角色。卫星通信系统、电话、数字计算机、电视、医学诊断设备和外科外科医学设备、流水线的机器人以及电力电子工具已经成为现代技术社会具有代表性的组成部分。作为一名电气工程师，你可以通过升级或精炼目前存在的系统，也可以通过研究和开发能够适应不断变化的社会需求的新系统，从而使自己也参与到这场正在火热进行的技术革命中。现在就让我们先简单了解一下电气工程的内容，使大家对本文的题目“电路使我们的生活更加方便舒适”，有一个更好的理解。最后我们介绍一下现代电路设计的方法。1. 电气工程概述电气工程是与生产、传送、测量电信号的系统密切

37、相关的一门专业。电气工程就是将物理学家的自然现象模型和数学家的数学工具结合在一起，从而创造一种新的模型，使这种模型能够适应人们的实际需求。电气系统在我们的生活中随处可见，在家庭、学校、车间中以及汽车中都可以看到它们的身影。电气系统主要有五个分支： 通信系统 计算机系统 控制系统 电力系统 信号处理系统下面我们就从这五个方面中各举一个例子，从而说明电气工程师是如何分析和设计和这些系统，也让读者对电气系统的广泛应用有一个感性认识。通信系统是产生、发射和分配信息的电子系统。举几个众所周知的例子：电视机、照相机、发射接收机和VCR、用来探测宇宙的射电望远镜、用来返回其它星球和我们地球图片的卫星通信系统

38、、用来确定飞机飞行坐标的雷达系统以及电话系统。图1 电话系统图1描述了现代电话系统的几个重要组成部分。从图片的开始向大家介绍这一系统，在一个电话系统里，话筒用来将声波信号转化为电信号。这些信号被传送到信号交换中心，在这里它们将和来自其它成千上万的电话电话信号组合在一起。组合的信号从交换中心发射出去；它们的信号形式由传播的距离决定。在我们的例子中，这些信号将通过埋藏在底下的同轴电缆传送到一个微波站。在这里，这些信号被转换为微波频率的信号，然后用发射天线发射到空间，再通过通信卫星发送到接收天线。微波接收站将微波信号转换成某种适于远距离传输的信号，比如说转化为光脉冲信号通过光缆传输出去。当到达第二个

39、交换中心后，组合的信号被分离开来，并且每个信号都发送给相应的电话，在电话这边此时的话筒当做扬声器，将收到的电信号还原回声波信号。在这个过程的每个阶段，电路都对信号进行了处理，起了重要作用。可以想象一下，真正的挑战在于设计、制造以及运行每个电路，每个电路都应该能够同时响应成千上万的电话呼叫并且还要保障高质量的连接。计算机系统是用电信号去处理信息，包括文字信息处理以及数学计算。计算机系统的大小不同，其功率强弱也不同。从袖珍计算器到个人电脑再到可以执行复杂任务的超级计算机（用来处理天气数据或建立复杂的有机分子化学反应模型）。计算机系统包括了微电路网络或者说是集成电路邮票大小的集成电路包含了成千上万的

40、电子器件，这些元件的运行速度和功率都接近于它们的物理极限，比如说光速和热力学定律的极限值。控制系统用电信号控制生产过程，比如炼油厂的说温度控制、压力控制和流速的控制；电子燃油喷射式汽车发动机里的燃油混合设备；电梯里面的机械装置电动机以及门和灯光控制系统；巴拿马运河的闸门控制装置。还有可以帮助飞机自动导航以及自动着陆的控制器也是我们所熟悉的控制系统。电力系统是用来产生和分配电力资源的。作为现代工业社会基础的电力资源，通常是有核电站、水电站及热电站（用煤、油或者气作燃料）。电能由横跨全国的的电网分配。设计和运行一个这样的系统最主要的挑战在于，要给整个大系统提供足够的冗余和控制，以确保整个系统中的任意一个小部分除问题都不会让一个城市、或一个区域断电。信号处理系统是用来处理代表信息的电信号。信号处理系统能够使电信号里包含的信息以更适合分析的形式存在。有许多种不同的信号处理方法。例如，图像处理系统收集到大量来自轨道气象卫星的数据，将这些数据压缩到可以接受到数量并且将其处理成适于晚间新闻的视频图像。计算机处理的X射线断层扫描（CT）又是另外