电子与通信技术专业英语Unit 3 lesson 15

1、PART1 Wireless Fidelity, popularly known as Wi-Fi, developed on IEEE 802.11 standards, is widely used technology advancement in wireless communication. As the name indicates, Wi-Fi provides wireless access to applications and data across a radio network. Wi-Fi sets up numerous ways to build up a con

2、nection between the transmitter and the receiver such as DSSS, FHSS, IR Infrared and OFDM. Wi-Fi provides its users with the liberty of connecting to the Internet from any place such as their home, office or a public place without the hassles of plugging in the wires. Wi-Fi is quicker than the conve

3、ntional modem for accessing information over a large network. With the help of different amplifiers, the users can easily change their location without disruption in their network access. Wi-Fi devices are compliant with each other to grant efficient access of information to the user. Wi-Fi location

4、 where the users can connect to the wireless network is called a Wi-Fi hotspot. Accessing a wireless network through a Lesson 15Wireless FidelityTextNew wordNotesExercisesTranslationVocabulary PART1Lesson 15Wireless Fidelityhotspot in some cases is cost-free while in some it may carry additional cha

5、rges. Many standard Wi-Fi devices such as PCI, miniPCI, USB, Cardbus and PC card, ExpressCard make the Wi-Fi experience convenient and pleasurable for the users. Wi-Fi uses radio networks to transmit data between its nodes. Such networks are made up of cells that provide coverage across the network.

6、 The more the number of cells, the greater and stronger is the coverage on the radio network. The most popular Wi-Fi technology such as 802.11b operates on the range of 2.40 GHz up to 2.4835 GHz band. This provides a comprehensive platform for operating Bluetooth strategy, cellular phones, and other

7、 scientific equipments. While 802.11a technology has the range of 5.725 GHz to 5.850 GHz and provides up to 54 Mbps in speed. 802.11g technology is even better as it covers three non-overlapping channels and allows PBCC. Device that can use Wi-Fi (such as a personal computer, video game console, Tex

8、tNew wordNotesExercisesTranslationVocabulary PART1Lesson 15Wireless FidelitySmartphone, tablet, or digital audio player) can connect to a network resource such as the Internet via a wireless network access point. Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or 802.11g

9、 might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors. Range also varies, as Wi-Fi is no exception to the physics of radio wave propagation, with frequency band. Wi-Fi in the 2.4 GHz frequency block has better range than Wi-Fi in the 5 GHz frequency block, and less range than the o

10、ldest Wi-Fi (and pre-Wi-Fi) 900 MHz block. Hotspot coverage can comprise an area as small as a single room with walls that block radio waves or as large as many square miles this is achieved by using multiple overlapping access points (as shown in Fig.15-1).TextNew wordNotesExercisesTranslationVocab

11、ulary PART1Lesson 15Wireless FidelityTextNew wordNotesExercisesTranslationVocabulary Fig.15-1 Wi-Fi ZonePART2New words and phrases:fidelity fideliti n.逼真；保真度access kses vt.使用，接近，获取hassle hsl n. 麻烦事plug pl v. 插上插头disruption disrpn n. 破裂，毁坏；中断console knsul n. 控制台，操纵台propagation ,prpein n. 传播，传输compris

12、e kmpraiz vt. 包含，包括；由组成overlapping ,uvlpi adj. 重叠的router raut n. 路由器TextNew wordNotesExercisesTranslationVocabulary PART2Phrases and ExpressionsDSSS (direct sequence spread spectrum)直接序列扩频OFDM (Orthogonal Frequency Division Multiplexing)正交频分复用FHSS (frequency-hopping spread spectrum)跳频扩频PCI（Periphera

13、l Component Interconnect） 周边元件扩展接口SSID (Service Set Identifier) 服务集标识符USB (Universal Serial Bus) 通用串行总线CardBus 具有总线控制功能的32位PC卡PBCC (Packet Broadcast Control Channel) 分组广播控制信道mini PCI 内置型无线网卡Express Card 扩展接口Mbps (megabits per second) 兆比特/秒New words and phrases:TextNew wordNotesExercisesTranslationVo

14、cabulary PART3Notes:1.Wireless Fidelity, popularly known as Wi-Fi, developed on IEEE 802.11 standards, is widely used technology advancement in wireless communi- cation. 译文：无线相容性认证，通常称为Wi-Fi ，它由IEEE 802.11标准发展而来，是在无线通信中被广泛应用的先进技术。IEEE：Institute Of Electrical And Electronics Engineers.USA美国电气与电子工程师协会

15、IEEE 802.11 standards：美国电气与电子工程师协会标准2.Wi-Fi sets up numerous ways to build up a connection between the transmitter and the receiver such as DSSS, FHSS, IR Infrared and OFDM. 译文：Wi-Fi在发射端和接收端之间设置了许多方法来建立连接，如扩频、跳频、红外的连接和正交频分复用。IR Infrared ：Ir是红外线的意思，常用说法Ir接口，也就是红外线接口。TextNew wordNotesExercisesTranslat

16、ionVocabulary PART33.Many standard Wi-Fi devices such as PCI, miniPCI, USB, Cardbus and PC card, ExpressCard make the Wi-Fi experience convenient and pleasurable for the users. 译文：许多标准的Wi-Fi设备，如PCI、miniPCI、USB、Cardbus以及PC卡、ExpressCard使得用户的Wi-Fi体验方便而愉快。PCI：PCI局部总线（Pedpherd Component Interconnect），一种由

17、英特尔（Intel）公司1991年推出的用于定义局部总线的标准。PC card：PC卡，一种用以给电脑及其他通讯和电子设备添加诸如存储器、大容量存储器、网络及无线通信等扩展装置的技术。miniPCI：Mini PCI插槽也同样是在PCI的基础上发展起来的，Mini PCI的定义与PCI基本上一致，只是在外型上进行了微缩。Express Card：由PCMCIA联盟推出的新规格，其优点是体积更小，传输速度更快，更适合移动系统。Notes:TextNew wordNotesExercisesTranslationVocabulary PART3USB：通用串行总线（Universal Serial

18、 Bus），是一新型界面规格，支持主系统与不同外设间的数据传输。USB允许外设在开机状态下插拔使用，USB具有易于使用、高带宽、可接多达127个外设、数据传输稳定、支持即时声音播放及影像压缩等特点。目前在国内市场可以见到的USB设备主要有扫描仪、数码相机、打印机、集线器和外置存储设备等。CardBus：PCMCIA推出的下一代高性能32位总线主控接口。它使现在只在桌面和较大系统上才拥有的高级功能可以移入CardBus卡，从而可以用在移动环境下。4.While 802.11a technology has the range of 5.725 GHz to 5.850 GHz and provi

19、des up to 54 Mbps in speed. 802.11g technology is even better as it covers three non-overlapping channels and allows PBCC.译文：虽然802.11a技术有着5.725 GHz到5.850 GHz的范围，并可提供高达Notes:TextNew wordNotesExercisesTranslationVocabulary PART354 Mbps（兆比特/秒）的速度，但802.11g技术甚至更好，它包括3个非重叠信道，并允许分组广播控制信道。802.11a technology

20、：IEEE（电机电子工程师协会，The Institute of Electrical and Electronics Engineers）于1997年公告的无线区域网路标准，适用于有线站台与无线用户或无线用户之间的沟通连结。 802.11a是802.11的衍生版，于5.8GHz频段提供了最高54 Mbps的速率规格，并运用orthogonal frequency division multiplexing encoding scheme以取代802.11的FHSS 或 DSSS。802.11g在2.4GHz频段上提供高于20 Mbps的速率规格。5.A typical Wi-Fi home

21、router using 802.11b or 802.11g might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors.译文：一个使用802.11b或802.11g的典型Wi-Fi家庭路由器可能有45米（150英尺）的室内范围和90米（300英尺）的户外范围。Ft：英尺的意思，feet 复数， foot 单数，直接用缩写ft即可。1 ft = 0.3048 m（米）Notes:TextNew wordNotesExercisesTranslationVocabulary PART4Exercises:1. W

22、rite T (True) or F (False) beside the following statements about the text.a. Satellite communication has become a part of everyday life in the late 1960s.b. An international telephone call is still not easy as a local call.c. We can see international events in our homes each night by the television

23、news program. d. Satellite communication brings the sights and sounds of the world via a television set.e. Now satellite-based communication only is a dream by a few inspired individuals.f. In l945, Arthur C. Clarke had developed a worldwide satellite system.g. Todays communications satellites, for

24、the most part, circling the earth at a rapid rate of speed.h.The satellite is stationary in the sky in relation to an observer on the earth.2. Match the following terms to appropriate definition or expression.a. satellite 1. create a world-wide communications b. slots 2. geostationary orbital positi

25、ons c. three satellites 3. a powerful communications tool TextNew wordNotesExercisesTranslationVocabulary PART4Exercises:3. Fill in the missing words according to the text.a. Fortunately though, _problem was eliminated in 1963 and 1964 through the launching of the Syncom satellite.b. Based on _ prin

26、ciples, three satellites placed in equidistant positions around the earth can create a _ system in that almost every point on the earth can be reached by satellite.c. This orbital slot also simplifies the establishment of the communications link between _ and_.d. Prior to this era, a ground stations

27、 _ had to physically track a satellite as it moved across the _.4. Translate the following paragraph into Chinese. The latter type of satellite system would have entailed the development of a very complex and cumbersome earth and space-based network. Fortunately though, this problem was eliminated i

28、n 1963 and 1964 through the launching of the Syncom satellite. Rather than circling the earth at a rapid rate of speed, the spacecraft appeared to be stationary or fixed in the sky. Todays communications satellites, for the most part, have followed suit and are now placed in what are called geostati

29、onary orbital positions or slots.TextNew wordNotesExercisesTranslationVocabulary PART4Exercises:802.11a technology：IEEE（电机电子工程师协会，The Institute of Electrical and Electronics Engineers）于1997年公告的无线区域网路标准，适用于有线站台与无线用户或无线用户之间的沟通连结。 802.11a是802.11的衍生版，于5.8GHz频段提供了最高54 Mbps的速率规格，并运用orthogonal frequency di

30、vision multiplexing encoding scheme以取代802.11的FHSS 或 DSSS。802.11g在2.4GHz频段上提供高于20 Mbps的速率规格。5.A typical Wi-Fi home router using 802.11b or 802.11g might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors.译文：一个使用802.11b或802.11g的典型Wi-Fi家庭路由器可能有45米（150英尺）的室内范围和90米（300英尺）的户外范围。Ft：英尺的意思，feet 复数， foot 单数，直接用缩写ft即可。1 ft = 0.3048 m（米）TextNew wordNotesExercisesTranslationVocabul