复习资料一《专业英语》词和词组 缩略写.docx

1、复习资料一专业英语词和词组 缩略写复习资料一：专业英语词和词组 缩略写Unit 11 抽样 量化 编码 sampling quantizing coding2 话路 speech channel3 幅值 amplitude value4 抽样频率 sampling frequency5 抽样速率 sampling rate6 脉冲流 stream of pulses7 重复率 repetition rate8 编码过程 coding process9 模拟信号 analog signal10 传输质量 transmission quality11 数字通信 digital communicat

2、ion12 数字传输 digital transmission13 噪声环境 noisy environment14传输路径 transmission path15 信噪比 signal to noise ratio16 信号电平 signal levels17 地面系统 terrestrial system18 噪声功率 noise power19 二进制传输 binary transmission20 反向操作 reverse operation21 8位码序列 8-digit sequence22 接收端 receiving terminal23 帧格式 frame format24 同

3、步字 synchronization word25 时分复用 TDM Unit 21 串行接口 serial interface2 显示终端 CRT terminal3 发送器和接受器 transmitter and receiver4 数据传输 data transmission5 数据流 data stream6 空闲状态 the idle state7 传号电平 mark level8 空号电平 space level9 起始位 start bit10 停止位 stop bit11 持续时间T秒 duration of T seconds12 奇遇校验位 parity bit13 错误标

4、志 error flag14 传输错误 transmission error15 下降沿 falling edge16 符号间的空格 intersymbol space17 接收机的定时 receiver timing18 本地时钟 local clock复习资料二：专业英语填空练习一选择合适的答案填空（正确答案已在题中用“”表示）:1.Urgent communications which could not because of no reply one end of the link could have dramatic consequences. A. establish, in B

5、. is established, with C. be establishing, to D. be established, at ()2.The operator of a local telephone switchboard had an option an optical or acoustical signal for the person over a wired network. A. transmit, search B. to transmit, searched () C. transmitting, searching D. to transmit, to searc

6、h3.The operation of a communication network needs a messaging system. A. to be complement with B. complement to C. to be complemented by () D. to complemented in4.Thus was born a new, but perpetually paging service as a one-way selective signaling system without speech. A. developing, defined () B.

7、developed, defining C. develop, define D. to develop, to define5.Today, certain models of pagers are even equipped with a display capability of optical messages of 10 to 80 characters. A. provide, consist B. provided, consisted C. providing, consisting () D. provision, consistant6.Paging systems usi

8、ng radio transmitters to this service remain currently in use mainly for service area not a few kilometers. A. dedicate, exceed B. dedicating, exceeded C. is dedicated, is exceeded D. dedicated, exceeding ()二选择合适的答案填空（正确答案已在题中用“”表示）:1.One of many reasons for a cellular mobile telephone system and it

9、 in many cities is the conventional mobile telephone system. A. develop, deploy B. to develop, to deploy C. developing, deploying () D. developed, deployed2.The ideal mobile telephone system would operate within a assigned frequency band and would serve an almost number of users in areas.A. limited,

10、 unlimited, unlimited ()B. limitation, limitation, limitationC. limit, limit, limitD. limiting,limiting, limiting3.LSI technology and mass production contribute to reduced cost in the future an average-income family should be able a mobile telephone unit. A. which, affording B. that, affordedC. when

11、, afford D. so that, to afford ()4.Microprocessors and minicomputers are now for controlling many complicated features and functions with less power and size was previously possible. A. used, than () B. use, this C. using, they D. usage, it5.On Jan. 4, 1979, the FCC Illinois Bell Telephone Co. a dev

12、elopmental cellular system in the Chicago area and make a limited offering of its cellular service to the public. A. authorize, conduct B. authorizing, conducting C. authorized, to conduct () D. to authorize, conducted6.Why 800 MHz? The FCCs decision 800 MHz was because of severe spectrum limitation

13、s at lower frequency bands. A. to choose, made () B. choose, to make C. choice, make D. choice, making三选择合适的答案填空（正确答案已在题中用“”表示）：1.Computer data in the public domain by a packet switched data network X. 25 protocols.A. are transported, based on() B. transports, base onC. transported, based on D. to t

14、ransport, base2.When the future BISDN network, one must all possible existing and future services. A. design, take B. designing, take into account () C. designed, account D. to design, taking3.A telex network telex information, i. e. messages of characters, at very low speed. A. transports, transpor

15、ted () B. transported, transport C. to transport, to transport D. transporting4.The NISDN cannot transport TV signals its limited bandwidth capabilities, so a special TV network is still . A. because, require B. with, to require C. due to, required () D. within, requiring5.Each network is only capab

16、le one specific service for it was intentionally designed. A. of transporting, which () B. transporting, one C. transport, where D. to transport, when四.选择合适的答案填空（正确答案已在题中用“”表示）1.The telephone contains a transmitter and receiver for back and forth analog voice and analog electrical signals. A. conver

17、t, in B. converting, between () C. conversion, to D. converted, into2.Each subscriber connecrs local loop to a switching center, as an end office.A. to, calling B. with, known C. the, know D. via, known ()3.The trunks are designed multiple voice-frequency circuits either FDM or synchronous TDM. A. c

18、arry, use B. carried, used C. to carry, to use D. to carry, using ()4.Although originally to service analog telephone subscribers, the telephone network handles substantial data traffic modem, and gradually being converted to a digital network. A. implemented, via () B. implementing, in C. to implem

19、ent, within D. design, on5.Designers have found it convenient these nodes into a hierarchy or tree topology, five classes of switching centers or nodes. A. organization, consist B. organize, consisting C. to organize, consisting () D. organizing, to consist复习资料四：专业英语短文翻译1.The reader may ask , how do

20、es the demultiplexer know which group of 8-digits relates to channel 1, 2, and so on ? Clearly this is important ! The problem is easily overcome by specifying a frame format , where at the start of each frame a unique sequence of pulses called the frame code , or synchronization word , is placed so

21、 as to identify the start of the frame. A circuit of the demultiplexer is arranged to detect the synchronization word, and thereby it knows that the next group of 8-digits corresponds to channel 1.2.Advances in audio, video and speech coding and compression algorithms and progress in Very Large Syst

22、em Integration technology influence the bit rate generated by a certain service and thus change the service requirements for the network. In the future, new services with unknown requirement will appear. For the time being it is yet unclear, e. g. what the requirement in terms of bit rate for HDTV w

23、ill be. A specialized network has great difficulties in adapting to changing or new service requirements.3.When the transmitter wishes to send data, it first places the line in a space level (i. e. , the complement of a mark) for one element period. This element is called the start bit and has a dur

24、ation of T seconds. The transmitter then sends the character, 1 bit at a time, by placing each successive bit on the line for a duration of T seconds, until all bits have been transmitted. Then a single parity bit is calculated by the transmitter and sent after the data bits. Finally, the transmitte

25、r sends a stop bit at a mark level (i. e. the same level as the idle state) for one or two bit periods. Now the transmitter may send another character whenever it wishes4.The cellular switch, which can be either analog or digital, switches calls to connect mobile subscribers to other mobile subscrib

26、ers and to the nationwide telephone network. It also contains data links providing supervision links between the processor and the switch and between the cell sites and the processor. The radio link carries the voice and signaling between the mobile unit and the cell site. Microwave radio links or w

27、ire lines carry both voice and data between the cell site and the MTSO.5.Todays telecommunication networks are characterized by specialization . This means that for every individual telecommunication service at least one network exists that transports this service. A few examples of existing public

28、networks are described belowComputer data are transported in the public domain by a packet switched data network (PSDN) based on X.25 protocol6.Todays telecommunication networks are characterized by specialization . This means that for every individual telecommunication service at least one network

29、exists that transports this service. A few examples of existing public networks are described below: Computer data are transported in the public domain by a packet switched data network (PSDN) based on X.25 protocols. Television signals can be transported in three ways: broadcast via radio waves usi

30、ng ground antenna, by the coaxial tree network of the community antenna TV (CATV) network or recently via a satellite, using the so-called direct broadcast system (DBS)7.By far the most popular serial interface between a computer and its CRT (显示器) terminal is the asynchronous serial interface . This

31、 interface is so called because the transmitted data and the received data are not synchronized over any extended period and therefore no special means of synchronizing the clocks at the transmitter and receiver is necessary. In fact, the asynchronous serial data link is a very old form of data tran

32、smission system and has its origin in the era of theteleprinter.8.At the receiving end of an asynchronous serial data link, the receiver continually monitors the line looking for a start bit. Once the start bit has been detected, the receiver waits until the end of the start bit and then samples the next N