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1、Unit 17 A.Text,Wireless Access System,New Words and Expressions,dispensability di5spensEbEl n. 可分配,可宽恕 conduit 5kCndit n. 管道, 导管 suburb 5sQbE:b n. 市郊, 郊区 mountainous 5mauntinEs adj. 巨大的 ministry 5ministri n. (政府的)部门 promote prE5mEut v. 促进, 提升 concerned kEn5sE:nd adj. 关心的, 有关的,withdraw wiT5drC: v. 收回
2、, 撤消 inconsistent 7inkEn5sistEnt adj. 矛盾的 designate 5dezineit v. 指定, 指派 regulation reju5leiFEn n. 规则, 规章 be inconsistent with 与不一致 in accordance with 根据 fall into 被分成,Technical Terms,Wireless Access System 无线接入系统 telecom carrier 电信运营商 every village accessible to telephone service 村村通电话 China Telecom
3、 中国电信 TDD(Time Division Duplex) 时分双工,the Radio Regulatory Bureau 无线规划委员会 the Ministry of Posts and Telecommunications(MPT) 邮电部 FDD(Frequency Division Duplex) 频分双工 Internet service provider(ISP) 因特网业务提供商 the MII(the Ministry of Information Industry) 信息产业部,Notes,1.With its advantages including the sho
4、rt construction period, dispensability with the laying of conduits and capability of both data and voice transmission, wireless access can partly or even entirely substitute for wire access. 无线接入的业务由于具有建设周期短、见效快、不需要铺设管道等优点，可传送话音和数据业务，可部分甚至全部地代替有线接入。 句子的主干结构是wireless access can substitute for wire ac
5、cess; With its advantages voice transmission是介词短语作原因状语，the short construction period译为: 建设周期短; dispensability with the laying of conduits译为:不需要铺设管道。,2.It is widely used by telecom carriers, which provide voice service largely, and newly emerging Internet service providers (ISPs) and potential local
6、access providers as well. 它已广泛应用于传统的以话音业务为主的电信运营商，也可应用于新兴的因特网业务提供商（ISP）以及未来专门经营本地接入业务的电信运营商。 句中which引导一个非限制性定语从句，修饰主句中的telecom carriers(电信运营商); and newly emerging and potential local access 都作介词by 的宾语。,3.Some years ago, in order to achieve the objective of making every village accessible to telephon
7、e service, the Ministry of Posts and Telecommunications (MPT) extensively used WA systems of this frequency band, promoting the rapid growth of the segments concerned. 前几年原邮电部为实现“村村通电话”，大量使用该频段的无线接入系统，由此带动了该项产业的迅速发展。 该句为简单句。句子主干结构是MPT used WA systems; 其中promoting segments concerned是现在分词作状语; concerne
8、d是过去分词作后置定语修饰segments。,4.Since these bands are inconsistent with those designated by the ITU for the use of 3G mobile communications, in accordance with the regulations of the Radio Regulatory Bureau of the MII, they can be used only in Beijing, Tianjin, Shanghai, Guangzhou, Shenzhen, Xiamen, Fuzhou
9、, Chengdu and Chongqing by the year 2002 and will be withdrawn and reallocated after that. 由于与国际电联指定的第三代移动通信的频段冲突，根据信息产业部无线电管理局的规定，该频段的无线接入系统只能在北京、天津、上海、广州、深圳、厦门、福州、成都、重庆等地使用至2002年止，到期后频率由国家收回，重新规划。 句中with those designated的designated 是过去分词短语作后置定语; 其中in accordance with of the MII是介词短语作行为方式状语。,. Try t
10、o match the following columns: 1.China Telecom 移动终端 2.Wireless Access System 电信运营商 3.telecom carrier 移动通信 4.mobile communications 无线规划委员会 5.Internet service provider 中国电信 6.Internet access 无线接入系统 7.mobile terminal 因特网接入 8.the Radio Regulatory Bureau 因特网业务提供商,Exercises,1.中国电信 2.无线接入系统 3.电信运营商 4.移动通信
11、5.因特网业务提供商 6.因特网接入 7.移动终端 8.无线规划委员会,.Here in column A are some of the important abbreviations used in telecom field. Write down the words that each stands for, then match them with their explanations in column B: A B 1.FDD: 国际电信同盟 2.TDD: 邮电部 3.CDMA: 数字移动通信系统 4.GSM: 时分复用 5.ITU: 码分多址 6.MPT: 频分复用,1.FDD
12、(Frequency Division) 频分复用 2.TDD(Time Division Duplex) 时分复用 3.CDMA(Code Division Multiplex Access) 码分多址 4.GSM(Global System for Mobile communication) 字移动通信系统 5.ITU(International Telecommunications Union) 国际电信同盟 6.MPT(the Ministry of Posts and Telecommunications) 邮电部,B. Reading Modes of Videoconferenc
13、ing New Words and Expressions videoconference 9vIdIEJ5kCnfErEns n. 视频会议 switch switF n. v. 交换; 开关 segment 5semEnt n. 段, 节, 片断 mechanism 5mekEnizEm n. 机械装置, 机制 sensitive 5sensitiv adj. 敏感的, 灵敏的,Technical Terms,desktop videoconferencing system 桌面视频会议系统 POTS(Plain Old Telephone Service) 旧电话业务 PSTN(the
14、public switched telephone network) 公用电话交换网digital service 数字业务 access rate 接入速率 BRI(Basic Rate Interface) 基本速虑接口 PRI(Primary Rate Interface) 主速率接口 signaling channel 信令信道 Token Ring 令牌环网 UDP(user datagram protocol) 用户数据报协议 error recovery mechanism 纠错机制,Exercises,Decide whether the following statement
15、s are true or false: 1.POTS has very low bandwidth, so there are a large number of desktop videoconferencing products. 2.ISDN is an older technology and is being replaced by Switched 56. 3.PRI provides 2 data channels of 64 kbps and one signaling channel of 16 kbps. 4.The difference between Ethernet and Token Ring is how clients gain access to the medium for transmission. 5.VDP is used by some videoconferencing
