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- 14课 -1、configuration 配置 Topologies 拓扑结构2、multidrop 插头式 ring or loop 环状或回路型 the mesh 网状3、simultaneously 同时 intelligence 情报4、perpheral equipment 外围终端 5、essentially /in nature 本质上6、vary considerable 在很大程度上7、hotel reservation systems 宾馆预订系统8、telecommunications network 电信网络9、plural 复数 mass media 大众媒体10、ATM = automatic teller machine11、simplex 单工,duplex 双工,HDX = half duplex, FDX= full duplex, F/FDX= full/full duplex 12、unidirectional 单向的,two-way alternate or either-way lines 双向交替或任一方向电路13、citizens band 民用波段14、postal system 邮政系统15、indefinitely 不确定的16、vice verse 反之亦然17、error control 差错控制，error detection 检错，error correction 纠错，echoplex 回送18、Trade-off 平衡，折中考虑，serial-parallel transmission串行和并行传输19、between the source and destination 在源地和目的地之间20、short-distance communications 近距离通信 21、and serial transmission is used for long-distance communications 远距离通信22、To insure an ordly flow of data between the line control unit and the modem,a serial interface is placed between them .23、in data communications,there are four types of synchronization(同步)that must be achieved:bit or clock synchronization,modem or carrier synchronization,character aynchronization,and message synchronization.1、Innovation 进步2、optical feeder links 光馈链接，digital compression techniques 数字压缩技术3、service integration 综合服务4、频分复用 frequency-division multiplexing 5、utilize 利用6、in this implementation 在这种实现方式中7、fiber-to-the-curb(FTTC) 光纤到路边8、视频点播 video on demand(VOD)9、telephony 电话， industry 行业10、the CATV industry is deploying bidirectional networks CATV 行业有必要拓展双向网络11、noted above 前面提到的12、atenuates 衰减13、nonadjacent 不毗连的，turn over 移交，subscribers 订户14、packet-switched wireless network 分组交换无线网络15、with the sponsorship 在-的资助下16、hub 中心17、on the order of 大约，在-数量级18、penetration 渗透无线局域网WLAN = wireless local area networktoehold 立足点notebook 笔记本backbone 骨干，integrated services 综合服务，multimedia Web access 多媒体网页访问公共信道信令 common channel signaling电话用户 subscriber telephone远程监控 remote monitoring同步传输 synchronous transmissionSDLC 同步数据链路控制 =synchronous data link control HDLC 高级数据链路控制=high-level data link control信息包 packet 自同步码 self-aynchronizing code 存储转发分组交换 store-and-forward packet-switchingLAN 局域网 = local area networkWAN 广域网 = wide area network异步传输模式(ATM)= Asynchronous Transfer modecell 信元，feeder 馈电线有线电视CATV = community antenna television障碍物 obstructionunidirectional 单向的nonadjacent 不相邻的，turn over 反复考虑with the sponsorship of 在-的资助下on the order of 与-相似的toehold 立足点 ，notebook 笔记本掌上电脑 palm-sized computer backbone 骨干，脊椎机顶盒 set-top TV box multiplex 多路复用ISDN = integrated services digital network 分组交换 packet-switch数字用户线路 DSL = digital subscriber linestore and forward 存储转发计算机串口 the serial port of computer devices它是短距离（少于30米）的低速率（为38kbps）传输标准This standard is for low bit rate(up to 38kbps) transmission over short diatances(less than 30m)每次一个字符 one character at a time可以添加一个奇偶校验比特用于检错 they can add a parity bit for error detection连续字符 successive characters时间间隔 time interval 当接收器检测到一个新字符的开始时When the receiver detects the beginning of a new character非双绞线 untwisted wires随着速率和距离的增加 as the rate and the distance increase - 17课 -1、 simultaneously 同时的2、 facsimile 传真3、 audio 音频4、 severe terrain 恶劣的地形5、 composite 合成6、 preemphasis network 预加重网络7、 deviator 偏差器8、 precede 在-之前9、 amplitude 丰富10、 artificial boost 人为的提升11、 IF = intermediate frequency 12、 Conventional 常见的13、 Mixer 混频器14、 Oscillator 振荡器15、 Multiply 倍频16、 Heterodyning 外差作用17、 Crystal oscillator 晶体振荡器18、 Factor 指数19、 Noncoherent 非相关的20、 Detector 检波器21、 Amplitude-versus-frequency characteristics幅频特性22、 载波比 carrier-to-noise ratio23、 信噪比 signal-to-noise ratio24、 Modulated 调制器25、 Deemphasis network 去加重网络26、 In digital microwave communications systems,phased shift keying is usually used to modulate the HF carrier by baseband signal27、 The receive module down-converts the Rf carrier to IF ,the IF AMP /AGC and equalizer circuits amplify and reshape the IF28、 The received RF signal enters the receiver through the channel separation network and bandpass filter29、 The term “digital radio”is used to refer to any microwave radio that transmits PCM carrier signals ,regardless of how or at what point the signals are inserted into the radio equipment.30、 The equalizer compensates for gain-versus-frequency nonlinearities and envelop delay distortion introduced in the system.18课1、 celestial body 天上的2、 space vehicle 太空交通工具3、 military 军事4、 GPS = global positioning system 全球定位系统5、 Navigation 航海，航行6、 Incorporate 合并7、 Frame 设计8、 Sector 部门9、 Aeronautical 航空10、 Geostationary orbital 同步轨道11、 Highly elliptical orbital 高椭圆轨道12、 Sole 基础13、 Briefcase 公文包14、 Significantly 值得一提的是15、 Alphanumeric pagers 文字数字寻呼机16、 Exploits 发射17、 Dual-mode phone 双模电话18、 蜂窝网络 cellular network19、 Multi-spot-beam coverage 多点波束覆盖技术20、 Inversely proportional to 反比于21、 Collective 集中地22、 Cruise liner 巡航船23、 Aircraft 飞机24、 Fixed 固定的25、 同步卫星 geostationary satellite26、 赤道 equator27、 近赤道卫星 equatorial orbit28、 The satellite link is probably the most basic in microwave communications since a line-of-sight path typically exists between the earth and space .29、 The ground segment consists of three main network elements :gateways,sometimes called fixed earth stations ,the network control center and the satellite control center .Multiplexing of signals 信号复用Multiple-access system多址系统Allocated to 分配Simultaneously 同时Transponder 转发器Inherent 内在的Self-interference 自干扰Critical 更关键的Throughput 吞吐量Multi-spot-beam 多点波束Spot beam 波束Contemporary 当代的Pedestrian 步行者Hence因此Municipal agencies 市政部门By virtue of 利用Intriguing 巧妙地
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