电子信息与通信工程专业英语lesson5(太原理工大学版)ppt课件

1、电子信息与通信工程专业英语,Chapter 5 Communication 第5章 通信,5.1 A Short History of Communication 通信简史 5.2 Wireless Communication Technology 无线通信技术 5.3 Optical Fiber Communication 光导纤维通信,电子信息与通信工程专业英语,5.4 Basic Networking Concepts for Computer Network 应用于计算机网络的基础网络概念,电子信息与通信工程专业英语,TEXT 文章 5.1 A Short History of Com

2、munication,1. Original technologies of communication 2. Communication at the speed of electricity,电子信息与通信工程专业英语,convergence n. 集中, 收敛, 融合 courier n. 送快信的人, 旅行从仆 circuit switching 电路交换 cyber terrorism n. 网络 dot-coms n. 网络企业 ecommerce n. 电子商务 heliograph n. 日光仪,电子信息与通信工程专业英语,Interface Message Processor

3、s n. 接口信息处理机 message switching 报文交换 monopoly n. 垄断 semaphore n. 信号灯 shackle vt. 束缚 skeptics n. 怀疑学派 sabbatical n. 学术假期 Telenet n. 远程通信网 Telecopier n. 远程复印机,电子信息与通信工程专业英语,No matter what career you enter, youll need to communicate with people. We believe that cultural, social, and personal experience

4、improves through more effective understanding and practice of communication. Communication Studies seek to understand communication and to improve its practice in a variety of relationships,电子信息与通信工程专业英语,We focus on two person and family communication, communication in small groups and in large orga

5、nizations, communication across communities, the nature of language and symbols, and the nature of argument and persuasion in political settings and in social movements,电子信息与通信工程专业英语,The history of communication can go back to thousands of years. However, the technologies that so many of us are addi

6、cted to today - mobile phones, the internet, satellite TV - are built on our achievements,电子信息与通信工程专业英语,Each new development has transformed the world we live in. An understanding of the journey we have taken to get where we are now shows that todays techniques are refinements of what came before. R

7、eally big revolutions may be still to come,电子信息与通信工程专业英语,1. Original technologies of communication,Communication begins with the first conversations between people. Fire and the smoke it produces may also have been used for simple communication between separated groups,电子信息与通信工程专业英语,The invention of

8、 the printing press in China some time after 300AD meant that the same message could be delivered to many people cheaply and more quickly than copying out the message many times by hand,电子信息与通信工程专业英语,2. Communication at the speed of electricity,With the discovery of electricity the speed and range o

9、f communication once again began to increase,电子信息与通信工程专业英语,The invention of techniques such as Morse code allowed complex messages to be transferred at very high speeds over this new medium. These had huge repercussions for many aspects of human life, for example, transport could be better coordinat

10、ed, government could transmit decisions to distant offices almost instantaneously, and businesses could work with more businesses over larger distances,电子信息与通信工程专业英语,The first amplitude modulation (AM) radio station began operating in Springfield, Mass., shortly after World War I, and the first freq

11、uency modulation (FM) station was authorized to operate by the Federal Communications Commission (FCC) in 1940,电子信息与通信工程专业英语,The first television station was authorized by the FCC in 1941 and the first CATV station system began several years later,电子信息与通信工程专业英语,See Table 5-1 Electrical communication

12、 history,电子信息与通信工程专业英语,At the same time as these developments in sound, people were working hard on capturing images. For hundreds of years artists and scientists had known that a small hole in the wall of a darkened room would project an image of the outside world on the opposite wall,电子信息与通信工程专业英语

13、,In 1814 Joseph Nicphore Nipce used this principle to project an image of the world onto chemically treated paper in a box, so the first photograph had been taken. Images from one part of the world could be brought to another,电子信息与通信工程专业英语,This allowed people in Tanzania to see what a London Street

14、looked like, and people in London to marvel at Maasai warriors dressed in their finery. In 1877, Eadweard Muybridge developed a camera which could take a series of photographs in rapid succession,电子信息与通信工程专业英语,He did this in order to win a bet on whether all a horses hooves left the ground when it r

15、an. He lost the bet, but invented the movie camera. By 1927 this had been combined with recorded sound, allowing people to share realistic experiences around the world,电子信息与通信工程专业英语,The technologies that we have discussed have all helped us store and transmit communication. All these technologies ar

16、e joining together in the form of computers and the internet,电子信息与通信工程专业英语,5.2 Wireless Communication Technology,1 Introduction 2. Wireless communication technology,电子信息与通信工程专业英语,In 1895, Guglielmo-Marconi opened the way for modern wireless communications by transmitting the three-dot Morse code for

17、 the letter S over a distance of three kilometers by electromagnetic waves,电子信息与通信工程专业英语,Introduction There are two fundamental aspects of wireless communication that make the problem challenging and interesting,电子信息与通信工程专业英语,First is phenomenon of fading: the time variation of the channel strengths

18、 due to the small-scale effect of multipath fading and shadowing by obstacles. Second, wireless users communicate over the air and there is significant interference between them,电子信息与通信工程专业英语,The interference can be between transmitters communicating with a common receiver, between signals from a si

19、ngle transmitter to multiple receivers, or between different transmitter-receiver pairs,电子信息与通信工程专业英语,How to deal with fading and interference is central to the design of wireless communication,电子信息与通信工程专业英语,There are many wireless communications technologies that can be differentiated by frequency,

20、 bandwidth, range, and applications,电子信息与通信工程专业英语,These categories range from wireless wide area networks (WWANs) which cover the widest geographic area, to wireless personal area networks (WPANs) which cover less than 10 meters,电子信息与通信工程专业英语,2. Wireless communication technology WPAN,A WPAN is a per

21、sonal area network, a network for interconnecting devices centered around an individual persons workspace, in which the connections are wireless,电子信息与通信工程专业英语,communication within about 10 meters used mainly as cable replacement technologies for data synchronization and connectivity for devices that

22、 are close to each other,电子信息与通信工程专业英语,Bluetooth wireless technology is the prevalent WPAN technology today. It operates in the 2.4-GHz unlicensed frequency band. Ultra-wideband (UWB) technology provides high bandwidth by transmitting at very low power across a broad frequency spectrum,电子信息与通信工程专业英语

23、,Wireless LANs,A Wire LAN (WLAN), which sometimes referred to as LAWN robust wireless network connectivity over a local area of approximately 100 meters operates in the 2.4-GHz frequency band at 11 Mbps,电子信息与通信工程专业英语,802.11 standards use the Ethernet protocol and Carrier Sense Multiple Access with C

24、ollision Avoidance (CSMA/CA) for path sharing and include an encryption method, the Wired Equivalent Privacy algorithm,电子信息与通信工程专业英语,WiFi focus on user authentication and encryption Multiple-Input Multiple-Output (MIMO) radio frequency (RF,电子信息与通信工程专业英语,WMAN,A wireless MAN, or WMAN a wireless commun

25、ications network that covers a large geographic area such as a city or suburb. back haul has the greatest short-term appeal,电子信息与通信工程专业英语,last mile could establish wireless as an alternative to residential broadband DSL/cable modem 2 to11GHz frequency range,电子信息与通信工程专业英语,Two WWAN technologies, inclu

26、ding Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA), dominate WWAN deployments worldwide,电子信息与通信工程专业英语,These two technologies are expected to evolve on parallel paths for the foreseeable future. We also recognize the importance of industry standards to widespr

27、ead adoption,电子信息与通信工程专业英语,In the same way that early competing WLAN technologies gave way to the IEEE 801.11b standard, it is important that the industry drive toward worldwide standardization in other wireless technologies,电子信息与通信工程专业英语,1.Optical fiber 2. Optical communication systems 3. Advantage

28、s of optical fiber communication,TEXT 5.3 Optical Fiber Communication,电子信息与通信工程专业英语,Terminology,aperture n. 孔径 attenuation n. 衰减 dielectric waveguide 介质波导 carbon dioxide laser 二氧化碳激光器 cleave vt. 劈开 cylindrical adj. 圆柱状的 electric arc n. 电弧 geometric optics 几何光学 graded index fiber 梯度型光纤，渐变型光纤，梯度折射率光纤

29、heterojunction n. 异质结 high numerical aperture 大数值孔径光纤,电子信息与通信工程专业英语,immune adj. 有免疫力的 indices n. index的复数 intersymbol interference 码间干扰 micron n. 微米 monochromaticity n. 单色性 meridional ray n. 子午射线 nanosecond n. 纳秒 neodymium laser 钕激光器 omnidirectional adj. 全方位的 pick up 获得 parabolic adj. 抛物线,电子信息与通信工程专

30、业英语,silica n. 二氧化硅 splice vt. 拼接 step index fiber 阶跃光纤，阶跃折射率光纤 sulphide n. 硫化物 transverse adj. 横向的 wavelength division multiplexing 分复用,电子信息与通信工程专业英语,The optical communication systems are different from microwave communication systems in many aspects: The carrier frequency is about 100 THz and the b

31、it rate is about 1T bit/s,电子信息与通信工程专业英语,Spreading of optical beams is always in the forward direction due to the short wavelengths. Suitable for free space communications above the earths atmosphere like intersatellite communications,电子信息与通信工程专业英语,1. Optical fiber,An optical fiber is a glass or plas

32、tic fiber that carries light along its length. Fiber optics is the overlap of applied science and engineering concerned with the design and application of optical fibers. Fibers which support many propagation paths or transverse modes are called multi-mode fibers (MMF,电子信息与通信工程专业英语,Fibers which can

33、only support a single mode are called single-mode fibers (SMF). Advantages low attenuation transmit signals over a wide bandwidth,电子信息与通信工程专业英语,Construction An optical fiber is a cylindrical dielectric waveguide that transmits light along its axis, by the process of total internal reflection. The fi

34、ber consists of a core surrounded by a cladding layer,电子信息与通信工程专业英语,Fig. 5-8 Optical fiber electromagnetic analysis,电子信息与通信工程专业英语,2. Optical communication systems,电子信息与通信工程专业英语,A light source is made of semiconductor A transfer function is required to define the power loss associated with the coupli

35、ng of the signal power from the light source to the fiber transmission line,电子信息与通信工程专业英语,Fiber The loss involved in either joining the fiber by a permanent splice or the use of a demountable connector is a transfer parameter to be included. Fiber-detector junction Photodetector Design algorithm,电子信

36、息与通信工程专业英语,3. Advantages of optical fiber communication,Wider bandwidth Low transmission loss Dielectric waveguide Signal security Small size and weight,电子信息与通信工程专业英语,EXERCISES,1.Please translate the following words and phrases into Chinese. 2.Please translate the following words and phrases into En

37、glish. 4. Answer the following questions according to the text,电子信息与通信工程专业英语,TEXT 5.4 Basic Networking Concepts for Computer Network,1. Introduction 2. Network topology 3. Internet address 4. Ports 5. Data transmission 6. Protocols,电子信息与通信工程专业英语,Terminology,ATM abbr. Asynchronous Transfer Mode异步传输模式

38、 centralize vt. 把集中起来 client/server network 主从网，客服网 conversely adv. 相反地 criteria n. 标准 DNS abbr. Domain Name System域名系统 Encrypt vt. 加密,将.译成密码 entity n. 实体 FDDI abbr. Fiber Distributed Data Interface光纤分布式数据接口 ISDN abbr. Integrated Services Digital Network综合 服务数字网 leased line 租用线，专用线,电子信息与通信工程专业英语,mem

39、onic adj.记忆的，记忆术的 peer-to-peer network 对等网 RFC abbr.Request For Comments请求讲解，Internet标准（草案） semantic adj.语义的 systematic adj.系统的，体系的 subnet n.子网络 syntax n. 语法，有秩序的排列 tiered application 分层应用 user authentication 用户认证,电子信息与通信工程专业英语,1. Introduction,A network that connects computers located within a relat

40、ively limited area, such as an office, a building or a campus, is known as a Local Area Network (LAN). A network that spans a wide geographical area, usually across cities, countries or even continents, is known as Wide Area Network (WAN,电子信息与通信工程专业英语,Their major difference lies in how data and info

41、rmation is stored. See Table 5-7,电子信息与通信工程专业英语,A LAN consists of networked computers, sometimes called workstations and other connecting devices. A WAN consists of two or more LANs connected via a communication channel that combines telephone lines, leased lines, microwave, or satellites. It can cov

42、er cities, countries, and continents,电子信息与通信工程专业英语,Fig. 5-12 shows four common connecting devices,Hubs Repeaters Bridges Routers,电子信息与通信工程专业英语,Fig. 5-12 Hardware components of networking,电子信息与通信工程专业英语,2. Network topology,The common network topologies are Bus,电子信息与通信工程专业英语,Star Ring,电子信息与通信工程专业英语,Usu

43、ally, more than one topology is used in a network. For example, in a school network system, a bus-star topology is usually used with a high bandwidth bus as the backbone. That backbone connects a number of star networks. The star network is formed in a computer room. Each workstation is connected to

44、 the hub using UTP cable and the backbone is often an optical fiber,电子信息与通信工程专业英语,Examples of LAN technology,Ethernet Fibber Distributed Data Interconnect (FDDI),电子信息与通信工程专业英语,Ethernet LAN,An Ethernet LAN is based on a bus topology and broadcast communication Token ring. Ethernet is a family of fram

45、e-based computer networking technologies for LANs. a standard for connecting computers into a LAN the name commonly used for IEEE 802.3 CSMA/CD,电子信息与通信工程专业英语,FDDI,FDDI specifies a 100-Mbps token-passing, dual-ring LAN using fiber-optic cable. Copper Distributed Data Interface (CDDI), has emerged to

46、provide 100-Mbps service over copper,电子信息与通信工程专业英语,3. Internet address,IP addresses are numeric quantities that are easy for computers to work with, but not for humans to remember. For example: 204.160.241.98. Domain Name System (DNS) servers are responsible for translating mnemonic textual Internet

47、 addresses into hard numeric Internet addresses,电子信息与通信工程专业英语,Each organization that maintains a computer network will have at least one server handling DNS queries. That server, called a name server, will hold a list of all the IP addresses within its network, plus a cache of IP addresses for recen

48、tly accessed computers outside the network. Each computer on each network needs to know the location of only one name server,电子信息与通信工程专业英语,When your computer requests an IP address, one of three things happens, depending on whether or not the requested IP address is within your local network. If the

49、 requested IP address is registered locally, that is, its within your organizations network; youll receive a response directly from one of the local name servers listed in your workstation configuration. In this case, there usually is little or no wait for a response,电子信息与通信工程专业英语,4. Ports,An IP por

50、t will identify a specific application running on an Internet host machine. A port is identified by a number, the port number. The number of ports is not functionally limited, in contrast to serial communications where only 4 ports are allowed,电子信息与通信工程专业英语,There are some port numbers which are dedicated for specific applications such as Tab