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1、2023年1月9日星期一,电子信息与通信工程专业英语,Chapter 5 Communication 第5章 通信,2023年1月9日星期一,电子信息与通信工程专业英语,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,2023年1月9日星期一,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
2、络概念,2023年1月9日星期一,电子信息与通信工程专业英语,TEXT 文章 5.1 A Short History of Communication,1.Original technologies of communication 2.Communication at the speed of electricity,2023年1月9日星期一,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
3、.电子商务heliograph n.日光仪,2023年1月9日星期一,电子信息与通信工程专业英语,Interface Message Processors 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,2023年1月9日星期一,电子信息与通信工程专业英语,No matter what career you enter,youll need to communicat
4、e with people.We believe that cultural,social,and personal experience 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.,2023年1月9日星期一,电子信息与通信工程专业英语,We focus on t
5、wo person and family communication,communication in small groups and in large organizations,communication across communities,the nature of language and symbols,and the nature of argument and persuasion in political settings and in social movements.,2023年1月9日星期一,电子信息与通信工程专业英语,The history of communica
6、tion can go back to thousands of years.However,the technologies that so many of us are addicted to today-mobile phones,the internet,satellite TV-are built on our achievements.,2023年1月9日星期一,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
7、 taken to get where we are now shows that todays techniques are refinements of what came before.Really big revolutions may be still to come.,2023年1月9日星期一,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 prod
8、uces may also have been used for simple communication between separated groups.,2023年1月9日星期一,电子信息与通信工程专业英语,The invention of 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
9、 by hand.,2023年1月9日星期一,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 of communication once again began to increase.,2023年1月9日星期一,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 a
10、t very high speeds over this new medium.These had huge repercussions for many aspects of human life,for example,transport could be better coordinated,government could transmit decisions to distant offices almost instantaneously,and businesses could work with more businesses over larger distances.,20
11、23年1月9日星期一,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 frequency modulation(FM)station was authorized to operate by the Federal Communications Commission(FCC)in 1940.,2023年1月9日星期一,电子信息与通信工程专业英语,The first t
12、elevision station was authorized by the FCC in 1941 and the first CATV station system began several years later.,2023年1月9日星期一,电子信息与通信工程专业英语,See Table 5-1 Electrical communication history,2023年1月9日星期一,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
13、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.,2023年1月9日星期一,电子信息与通信工程专业英语,In 1814 Joseph Nicphore Nipce used this principle to project an image of the world onto chemical
14、ly treated paper in a box,so the first photograph had been taken.Images from one part of the world could be brought to another.,2023年1月9日星期一,电子信息与通信工程专业英语,This allowed people in Tanzania to see what a London Street looked like,and people in London to marvel at Maasai warriors dressed in their finery
15、.In 1877,Eadweard Muybridge developed a camera which could take a series of photographs in rapid succession.,2023年1月9日星期一,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 ran.He lost the bet,but invented the movie camera.By 1927 this had been com
16、bined with recorded sound,allowing people to share realistic experiences around the world.,2023年1月9日星期一,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 are joining together in the form of computers and the internet.,202
17、3年1月9日星期一,电子信息与通信工程专业英语,5.2 Wireless Communication Technology,1 Introduction2.Wireless communication technology,2023年1月9日星期一,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 the letter S over a distance of three ki
18、lometers by electromagnetic waves.,2023年1月9日星期一,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.,2023年1月9日星期一,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 due to the sm
19、all-scale effect of multipath fading and shadowing by obstacles.Second,wireless users communicate over the air and there is significant interference between them.,2023年1月9日星期一,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 singl
20、e transmitter to multiple receivers,or between different transmitter-receiver pairs.,2023年1月9日星期一,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.,2023年1月9日星期一,电子信息与通信工程专业英语,There are many wireless communications technologies that can be diff
21、erentiated by frequency,bandwidth,range,and applications.,2023年1月9日星期一,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.,2023年1月9日星期一,电子信息与通信工程专业英语,2.Wireless co
22、mmunication technology WPAN,A WPAN is a personal area network,a network for interconnecting devices centered around an individual persons workspace,in which the connections are wireless.,2023年1月9日星期一,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
23、 data synchronization and connectivity for devices that are close to each other.,2023年1月9日星期一,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
24、at very low power across a broad frequency spectrum.,2023年1月9日星期一,电子信息与通信工程专业英语,Wireless LANs,A Wire LAN(WLAN),which sometimes referred to as LAWN robust wireless network connectivity over a local area of approximately 100 metersoperates in the 2.4-GHz frequency band at 11 Mbps,2023年1月9日星期一,电子信息与通信工
25、程专业英语,802.11 standards use the Ethernet protocol and Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA)for path sharing and include an encryption method,the Wired Equivalent Privacy algorithm.,2023年1月9日星期一,电子信息与通信工程专业英语,WiFi focus on user authentication and encryption Multiple-Input Mul
26、tiple-Output(MIMO)radio frequency(RF),2023年1月9日星期一,电子信息与通信工程专业英语,WMAN,A wireless MAN,or WMANa wireless communications network that covers a large geographic area such as a city or suburb.back haul has the greatest short-term appeal,2023年1月9日星期一,电子信息与通信工程专业英语,last mile could establish wireless as an
27、alternative to residential broadband DSL/cable modem 2 to11GHz frequency range,2023年1月9日星期一,电子信息与通信工程专业英语,Two WWAN technologies,including Global System for Mobile Communications(GSM)and Code Division Multiple Access(CDMA),dominate WWAN deployments worldwide.,2023年1月9日星期一,电子信息与通信工程专业英语,These two tech
28、nologies are expected to evolve on parallel paths for the foreseeable future.We also recognize the importance of industry standards to widespread adoption.,2023年1月9日星期一,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
29、 industry drive toward worldwide standardization in other wireless technologies.,2023年1月9日星期一,电子信息与通信工程专业英语,1.Optical fiber 2.Optical communication systems 3.Advantages of optical fiber communication,TEXT 5.3 Optical Fiber Communication,2023年1月9日星期一,电子信息与通信工程专业英语,Terminology,aperture n.孔径attenuation
30、 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heterojunction n.异质结high numerical aperture 大数值孔径光纤,2023年1月9日星期一,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 interfere
31、nce 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,2023年1月9日星期一,电子信息与通信工程专业英语,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
32、,2023年1月9日星期一,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 bit rate is about 1T bit/s.,2023年1月9日星期一,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
33、the short wavelengths.Suitable for free space communications above the earths atmosphere like intersatellite communications,2023年1月9日星期一,电子信息与通信工程专业英语,1.Optical fiber,An optical fiber is a glass or plastic fiber that carries light along its length.Fiber optics is the overlap of applied science and e
34、ngineering concerned with the design and application of optical fibers.Fibers which support many propagation paths or transverse modes are called multi-mode fibers(MMF).,2023年1月9日星期一,电子信息与通信工程专业英语,Fibers which can only support a single mode are called single-mode fibers(SMF).Advantageslow attenuatio
35、n transmit signals over a wide bandwidth.,2023年1月9日星期一,电子信息与通信工程专业英语,ConstructionAn optical fiber is a cylindrical dielectric waveguide that transmits light along its axis,by the process of total internal reflection.The fiber consists of a core surrounded by a cladding layer,2023年1月9日星期一,电子信息与通信工程专业
36、英语,Fig.5-8 Optical fiber electromagnetic analysis,2023年1月9日星期一,电子信息与通信工程专业英语,2.Optical communication systems,2023年1月9日星期一,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 coupling of the signal power from the light sou
37、rce to the fiber transmission line.,2023年1月9日星期一,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,2023年1月9日星期一,电子信息与通信工程专业英语,3.Ad
38、vantages of optical fiber communication,Wider bandwidth Low transmission loss Dielectric waveguide Signal security Small size and weight,2023年1月9日星期一,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 Englis
39、h.4.Answer the following questions according to the text.,2023年1月9日星期一,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 topology3.Internet address4.Ports5.Data transmission6.Protocols,2023年1月9日星期一,电子信息与通信工程专业英语,Terminology,ATM abbr.Asynchronous Transfer
40、Mode异步传输模式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,2023年1月9日星期一,电子信息与通信工程专
41、业英语,memonic 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,2023年1月9日星期一,电子信息与通信工程专业英语,1.Introduction,A network that connects computers located
42、within a relatively 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).,2023年1月9日星期一,电子信息与通信工程专业英语,Their major difference lies
43、in how data and information is stored.See Table 5-7.,2023年1月9日星期一,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,microwa
44、ve,or satellites.It can cover cities,countries,and continents.,2023年1月9日星期一,电子信息与通信工程专业英语,Fig.5-12 shows four common connecting devices,HubsRepeatersBridgesRouters,2023年1月9日星期一,电子信息与通信工程专业英语,Fig.5-12 Hardware components of networking,2023年1月9日星期一,电子信息与通信工程专业英语,2.Network topology,The common network t
45、opologies are Bus,2023年1月9日星期一,电子信息与通信工程专业英语,Star Ring,2023年1月9日星期一,电子信息与通信工程专业英语,Usually,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.
46、The star network is formed in a computer room.Each workstation is connected to the hub using UTP cable and the backbone is often an optical fiber.,2023年1月9日星期一,电子信息与通信工程专业英语,Examples of LAN technology,EthernetFibber Distributed Data Interconnect(FDDI).,2023年1月9日星期一,电子信息与通信工程专业英语,Ethernet LAN,An Ethe
47、rnet LAN is based on a bus topology and broadcast communication Token ring.Ethernet is a family of frame-based computer networking technologies for LANs.a standard for connecting computers into a LAN the name commonly used for IEEE 802.3 CSMA/CD,2023年1月9日星期一,电子信息与通信工程专业英语,FDDI,FDDI specifies a 100-M
48、bps token-passing,dual-ring LAN using fiber-optic cable.Copper Distributed Data Interface(CDDI),has emerged to provide 100-Mbps service over copper.,2023年1月9日星期一,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 rememb
49、er.For example:204.160.241.98.Domain Name System(DNS)servers are responsible for translating mnemonic textual Internet addresses into hard numeric Internet addresses.,2023年1月9日星期一,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.Tha
50、t server,called a name server,will hold a list of all the IP addresses within its network,plus a cache of IP addresses for recently accessed computers outside the network.Each computer on each network needs to know the location of only one name server.,2023年1月9日星期一,电子信息与通信工程专业英语,When your computer r
