[互联网]通信英语教程.ppt

《通信与电子信息专业英语教程》 陈杰美、刘洪盛、饶渐升 Lesson 15 Communication Networks 《通信与电子信息专业英语教程》 陈杰美、刘洪盛、饶渐升 电子工业出版社 Lesson 15 Communication Networks Backgrounds Text tour Language in use Vocabulary Structure Reading/writing techniques Backgrounds Terminology Switch multiplex (statistical multiplexing, time-division multiplexing, frequency-division multiplexing ) Internet Protocol multiple access modem Backgrounds Terminology Header, trailer cyclic redundancy check (CRC) Ethernet LAN /WAN Cell route switch n. 开关, 电闸, 转换 vt. 转换, 转变 circuit switching 电路交换 packet switching 包交换，分组交换 store-and-forward packet-switching 存储转发分组交换 multiplex 多元的，复用的 statistical multiplexing 统计复用 time-division multiplexing 时分复用 frequency-division multiplexing 频分复用 demultiplex 解复用的 Internet Protocol Internet协议 multiple access 多路存取（访问） 通信(多个地面站用一个卫星进行通信)] 多元联结, 多址方式, 多重存取 modem 调制解调器，该词是由mo(dulator)和dem(odulator)合成 header, trailer Header 信头 Trailer 包尾 cyclic redundancy check (CRC) 循环冗余校验 Ethernet 以太网 LAN /WAN 局域网/ 广域网 LAN=Local Area Network WAN=Wide Area Network Cell 信元 route 路由 Lesson 15 Communication Networks Backgrounds Text tour Language in use Vocabulary Structure Reading/writing techniques Text tour Outline Telephone networks Computer Networks Cable Television Networks Wireless Networks Telephone networks This is accomplished by circuit switching, where “circuit” refers to the capability of transmitting one telephone conversation along one link. 这是由电路交换来完成的，这里“电路”指的是在一个连接中只能传输一组会话。 Telephone networks The additional bits are used to accommodate DS-0 channels with rates that deviate from the nominal 64 kbps because the signals are generated using clocks that are not perfectly synchronized. 由于在信号生成的时候时钟并非完全同步的，所以DS-0信道中的信号要添加附加位来与该信道64Kbps的速率保持一致。 Telephone networks ISDN makes available to subscribers the digital transmission facilities that were previously used between the switches of the network, thus extending the digital transmission all the way to the users.