电专业英语阅读教程05

大连理工大学出版社同名教材配套电子教案Specialty English《电专业英语阅读教程》（第二版）温丹丽高源制作大连理工大学出版社Unit Five Computer Simulation and Aided Design▪Passage One Introduction to Computer Simulation▪Passage Two CAD/CAM▪Passage Three Introduction to Protel99SE▪Passage Four What is a VHDL?▪Passage Five Applications of EDA in Circuit Experiments ▪构词法（Ⅱ）名词前缀与后缀Passage One Introduction to Computer SimulationTraining target: In this part, our target is to train your reading comprehension. We have made the flexible sentences strong black and marked the subject, predicate and object of them. Try to grasp the main idea of these sentences.Speciality VocabulariesComputer simulation计算机仿真ecology生态学，[社会]环境适应学climatology气候学astrophysics天体物理学Passage One Introduction to Computer Simulation Notes:1 Computers have long been used to create numerical and logical modelsor simulations (simulation仿真)of real-world systems.2In many cases, testing a real-world system can be prohibitively expensive or outright （outright完全的，全部地）impossible.3Seeing how an automobile collapses when it hits a barrier is an example of an expensive exercise to conduct in reality.4 An example of an impossible-to-realize （impossible-to-realize不可能实现的）experiment would be estimating the environmental damagewrought（wrought 做成的，形成的）by an asteroid colliding with the earth. At present, we lack the ability to conduct this experiment in actuality.Notes:5 Many systems are so complex that their correctness andbehavior can be easily or confidently predicted, eitheranalytically or through experience and intuition.6 Without such tools, the development of even moderately complex ICs is vastly （vastly 非常）more difficult and expensive, and in many cases, nearly impossible.7 Beyond allowing engineers to see if their designs work, computer simulations allow the rapid comparison ofalternative designs.8 Computer modeling and simulation has greatly aided research into complex systems in such fields as ecology,climatology, and astrophysics.Unit Five Computer Simulation and Aided DesignPassage One Introduction to Computer SimulationUnit Five Computer Simulation and Aided DesignPassage Two CAD/CAMTraining target: In this part, our target is to train your reading speed; you should pay more attention to ―word group‖. Treating a group of words as a whole unit is a short cut to save your time. We have underlined the word groups in some sentences, and the rest can be practiced by yourself. If there are some new words, you may cover the note area with a piece of paper and try to guess their meaning without using the dictionary.Speciality Vocabulariesdynamic动力的；动态的integrate使完整，使一体化interface界面，接口modification修改，更改optimization最佳化，优化strain应变stress压力，应力CAD(computer-aided design)计算机辅助设计CAM(computer-aided manufacturing)计算机辅助制造Passage Two CAD/CAMNotes:1 CAD/CAM is a term which means computer-aided design and computer-aidedmanufacturing.2 Ultimately（ultimately 最终；最重要的是）, CAD/CAM will provide thetechnology base for the computer-integrated factory of the future.3 There are many reasons for using CAD; the most potent driving force iscompetition.4The possibility of importing different graphic file formats and scanning of material (photographs) into a CAD program is also an asset especially as the image can be manipulated, retouched and animated.5 Computer-aided design (CAD) can be defined as the use of computer systems toassist in the creation, modification, analysis, or optimization of a design like the picture below (Fig.5.1).Passage Two CAD/CAMNotes:6 Examples of these application programs include stress-strain analysis of components, dynamic response of mechanisms, heat-transfer calculations, and numerical control part programming.7 Computer-aided manufacturing (CAM) can be defined as the use computer systems to plan, manage, and control the operations of manufacturing plant through either direct or indirect computer interface with the plant's production resources. .8 In addition to the applications involving a direct computer-process interface for the purpose of process monitoring and control, computer-aided manufacturing also includes indirect applications in which the computer serve a support role in the manufacturing operations of the plant.Passage Three Introduction to Protel99SETraining target: In this part, you should try your best to form good reading habits .In order to avoid your ill habits such as regression, you should keep reading the paragraphs from the beginning to the end without stopping.Speciality VocabulariesPrinted Circuit Board印刷电路板Signal layer信号层Mechanical layer机械层motherboard母板interconnecter互连器EMC（Electro Magnetic Compatibility）电磁兼容性Text:The new technologies in Protel99SE include:Design Explorer When you start Protel99SE,the Protel Design Explorer appears.This is your interface to your designs,with the tools that you use to edit them.Passage Three Introduction to Protel99SESmart Doc In Protel99SE all your design documents are stored in a single design database. Not only can you include the documents created by the Protel editors;you can also include any other design documents created by any application in Windows.Smart Tools All the protel tools are accessed though the Design Explorer.You can edit the schematic（schematic原理图）design alongside(alongside在旁)the PCB,and view the simulation results alongside the schematic one.As well as(as well as又)the Protel tools, Smart Tools technology also allows you to edit non-Protel documents inside the Design Explorer.Documents that are created by an Active Doc server(an extension of OLE)can be edited directly in the Design Explorer.Active Doc servers include Microsoft Word and Excel,and the Visio tools.Smart Team Now that you can store all the design documents in a single design database, your whole team will need access to it.With Protel99SE is easy,there are no restrictions （restriction限制）on the number of team members that can be working in the same design database.To help manage the team you can define team member permissions and each member can view what documents are currently open,and lock documents as needed.Passage Three Introduction to Protel99SEMixed-Signal Circuit Simulation Protel99SE includes an all-new analog/digital circuit simulator,which is SPICE3f5compliant.Signal Integrity Analysis, today's high-speed clocks and fast-switching logic,means that PCB design is more than placing and impedance,propagation delays,signal quality, reflections,and EMC are issues that every designer must understand. Protel99SE's integrated signal integrity（integrity完整性）tool accurately models（model模型）and analyzes（analyzes分析）the behavior （behavior行为）of the board,helping you get it right the first time.What is PCB?PCB Stands for―Printed Circuit Board‖.A PCB is a thin board made of fiberglass or a similar material.Electrical wires are―printed‖onto the board, connecting the microprocessor to other components on the board.Some examples of PCBs include motherboards,RAM chips,and network interface cards.Passage Three Introduction to Protel99SEPCB(Printed Circuit Board)is the baseboard for assembling electronic components and the printed board for forming connections between contacts（contact[电]接点，触点）and printed components on the universal substrate according to the predesign,the main function of which is providing connections to link various electronic components together as the prearranged circuits and acting as a relay.So PCB is the key electronic interconnecter.The PCB of Z80microprocessor is shown in Fig.5.3.Printed circuit boards are sometimes abbreviated as―PC boards‖,which is fitting, since the boards are commonly used in personal computers.However,PCBs are also found in other types of electronic devices,such as radios,televisions,and computer monitors.Because PCBs are relatively flat,they can also be used in thin devices such as laptops and portable music players.Passage Three Introduction to Protel99SEDefining a new PCBTo begin the PCB design phase of a project,create a new PCB document in your design database.Before bringing design information from the schematic,you should first create the mechanical and electrical board outline for your board,and configure（configure设定）the layer stack（stack堆栈）.The mechanical outline（outline略图，轮廓）defines the physical（physical物理的）shape and size of the board,and also includes items such as dimension（dimension尺寸线）detail,other company and fabrication（fabrication制作）specific（specific明确的）information.This information is usually placed on the four Mechanical layers.The electrical board outline defines the routing and component placement limits of the board.This is done by defining an outline of the board on the Keep Out layer.The Keep Out layer is a special layer that allows you to define―legitimate‖（legitimate合法的）placement and routing areas in the PCB workspace.Generally you would define an area which is the same as the physical board outline.All signal-layer objects and routing（routing布线）would then be confined within this area.You could also define areas on the Keep Out layer within the board outline to act as"no go"areas for placement and routing.Passage Four What is a VHDL?Training target:In this part,our target is to train your reading comprehension. When reading this passage,pay attention to the questions.What is a VHDL?VHDL is the VHSlC（VHSIC超高速集成电路）Hardware Description Language.VHSIC is an abbreviation for Very High Speed Integrated Circuits.Which aspects is VHDL used in?VHDL is a programming language that has been designed and optimized for describing the behavior of digital circuits and systems.VHDL is becoming increasingly （increasingly愈加）popular as a way to capture complex digital electronic circuit for both simulation and synthesis（synthesis综合，合成）.It can describe the behavior and structure of electronic systems,but is particularly suited as a language to describe the structure and behavior of digital electronic hardware designs,such as ASIC s and FPGA s as well as conventional digital circuits.Passage Four What is a VHDL?Which two kinds of tools do the VHDL language hasDigital circuits captured using VHDL can be easily simulated,and more likely to be synthesized into multiple target technologies,and can be archived for later modification and reuse.VHDL is a rich and powerful language.Simulation and synthesis are the two main kinds of tools which operate on the VHDL language.VHDL does not constrain the user to one style of description.VHDL allows designs to be described using any methodology—top down,bottom up or middle out!VHDL can be used to describe hardware at the gate level or in a more abstract way.Successful high level design requires a language,a tool set and a suitable methodology.Passage Four What is a VHDL?Which levels of abstraction does VHDL include?VHDL can be used to describe electronic hardware at many different levels of abstraction.When considering the application of VHDL to FPGA/ASIC design,it is helpful to identify and understand the three levels of abstraction shown in Fig.5.4—algorithm,register transfer level(RTL),and gate level.Algorithms are not synthetical,RTL is the input to synthesis,gate level is the output from synthesis. The difference between these levels of abstraction can be understood in terms of timing.Passage Four What is a VHDL?How is a design described?A design description or model,written in VHDL,is usually run through a VHDL simulator to demonstrate the behavior of the modeled system.Simulating a VHDL design model requires simulated stimulus,a way of observing the model during simulation,and capturing the results of simulation for later inspection. Designer usually creates a set of test cases,for inputs and expected results,to verify the function of the design.This file is called Testbench.What is the goal of application of VHDL?Some parts of VHDL can be used with logic synthesis tools for producing a physical design.In particular,many VLSI(Very Large Scale Integrated Circuit) gate-array vendors can convert a VHDL design description into a gate level netlist from which a customized integrated circuit component can then be built. Hence the application of VHDL is for:•Documenting a design•Simulating the behavior of a design•Directly synthesizing logicPassage Five Applications of EDA in Circuit ExperimentsTraining target: Read the following reading materials, and use the reading skills mentioned in the passages above. You may also choose some parts of this passage to practice.As electronics products become more and more complex,driving additional functionality into smaller and cheaper devices,the design and testing process gets more difficult.In the design space, there is tremendous pressure on the design tool vendors to open their products so users can have a streamlined and connected design tool chain.Electronic design automation(EDA)software can incorporate more and more technology into their basic schematic modeling and simulation tools,and then automate the conversion of these electrical designs into physical chips or boards.In the manufacturing space,more companies are adopting a flexible modular hardware and software approach based on virtual instrumentation shown in Fig.5.5so they can easily add measurement components to their modular test architecture to match the growing functionality of their products.Both of these trends, toward more open,modular,and compatible software tools in the design and test areas,represent progress for the design engineer and test engineer respectively.However,these two basic functions–design and test–must work together to get a product from concept to delivery.It is the gap between design and test that remains neglected by the tool vendors.Passage Five Applications of EDA in Circuit ExperimentsEven if you are not using Multisim today, you will likely find it increasingly necessary to do so in the future. It offers the perfect environment for experienced and novice VHDL users alike.What is Multisim?Multisim is a complete system design tool that offers a large component database, schematic entry, full analog/digital SPICE simulation, VHDL/Verilog HDL design entry/simulation, FPGA/CPLD synthesis, and seamless transfer to PCB layout packages. It offers a single, easy-to-use graphical interface for all your design needs.Multisim provides all the advanced functionality you need to take designs from specification to production. And because the program tightly integrates schematic capture, simulation, Printed Circuit Board (PCB) layout and programmable logic, you can design with confidence.About the Circuit Design ProcessMultisim supports every step of the overall circuit design process, which typically includes the following phases:Passage Five Applications of EDA in Circuit Experiments1.Entering the design into the software tool being used.2.Verifying that the behavior of the circuit matches expectations. This step isperformed using simulation, and analysis.3.Modifying the circuit design if the behavior does meet expectations, and returningto step 2.Depending on how the circuit is to be physically implemented, passing the design through the appropriate process.This explains the simulation of PCB-level circuits. This, by default, is primarily the function of the Multisim SPICE simulator. In cases where the PCB circuit makesuse of a complex digital chip modeled with VHDL or Verilog HDL (including aprogrammable logic device), Multisim automatically simulates that device with the correct VHDL or Verilog HDL simulator. This process is invoked automaticallyduring simulation of the PCB-level circuit, is performed simultaneously with the SPICE simulation, and is transparent to you.To view the results of your simulation, you will need to use either a virtual instrument or be running an analysis in order to display the simulation output. This output willinclude the combined results of all Multisim simulation engines (SPICE, VHDL,Verilog HDL).VHDL SimulationUnit Five Computer Simulation and Aided DesignPassage Five Operational AmplifiersMultisim employs a specialized VHDL simulator which simulates, not at the SPICE level using schematic design entry, but at the behavioral language level. VHDL is one of the two most widely used behavioral languages, commonly used for designing and modeling:Programmable logic devices such as CPLDs and FPGAs complex digital chips, such as memory, CPUs, microcontrollers, and other devices which could not be reasonably modeled using SPICE.构词法（Ⅱ）名词前缀与后缀在英语构词法中，利用前缀和后缀可以构成新词，可以赋予一个词以新的含义。