【正文】 B. to perform these functionsC. to transmit the voice channelsD. to sample the amplitude value答案：D34. Digital transmission ( ) for overing noisy environments.A. provides a programB. provides a powerful methodC. provides the thermal lowlevel noiseD. provides the signaltonoise ratio答案：B35. The signal ( ) is very weak.A. within terrestrial systemB. within munication equipmentC. received from a satellite D. in a particular message答案：C36. The shape of the transmitted signal are most easily affected by the noise and attenuation ( ).A. introduced by the transmission pathB. introduced by the satelliteC. introduced by the equipmentD. introduced by the codec答案：A37. The demultiplexer knows which group of 8digits relates to channel ( ).A. by choosing digital transmissionB. by identifying the synchronization wordC. by word interleavingD. by binary transmission答案：B21 / 21。通信英語I單項(xiàng)選擇1． 抽樣頻率a. sampling rate b. repetition rate c. sampling frequency答案：c2． 數(shù)字通信a. digital munication b. digital transmission c. transmission path答案：a3． 幀格式a. synchronization word b. frame format c. reverse operation答案：b4． 噪聲功率a. noisy environment b. signal levels c. noise power答案：c5． 含噪聲的環(huán)境a. signal levels b. noisy environment c. noise power答案：b6． 模擬信號a. speech channel b. analog signal c. amplitude value答案：b7． 脈沖流 a. stream of pulses b. receiving terminal c. terrestrial system答案：a8． 傳輸路由a. transmission path b. transmission quality c. binary transmission答案：a9． 互聯(lián)網(wǎng)a. network resource b. Internet c. interconnected systems答案：b10． 命令a. copy b. host c. mand答案：c11． 拷貝a. address b. mouse c. copy答案：c12． 搜索工具a. user interface b. searching tools c. electronic mail答案：b13． 存取 a. access b. protocol c. copy答案：a14． 網(wǎng)絡(luò)資源a. textual messages b. remote terminals c. network resources答案：c15． 文本信息a. information services b. hypertext protocol c. textual messages答案：c16． 頻譜a. bandwidth b. spread spectrum c. frequency band答案：b17． 移動(dòng)手機(jī)a. mobile subscriber b. mobile unit c. service performance答案：b18． 頻帶a. frequency spectrum b. frequency band c. spread spectrum答案：b19． 蜂窩交換機(jī)a. cellular switch b. cellular site c. mobile unit答案：a20． 單邊帶a. singlesideband b. bandwidth c. service area答案：a21． 服務(wù)區(qū)a. service area b. service performance c. service capability答案：a22． 移動(dòng)用戶a. mobile unit b. mobile subscriber c. mobile transceiver答案：b23． 微處理器a. subsystems b. utilization c. microprocessor答案：c24． 無線機(jī)架a. radio cabinet b. antenna c. mobile unit答案：a25． 電路交換a. packet switching b. circuit switching c. message switching答案：b26． 分組交換a. packet switching b. circuit switching c. message switching答案：a 27． 報(bào)文交換a. packet switching b. circuit switching c. message switching答案：c 28． 專用電路a. dedicated circuit b. error control c. return signal答案：a29． 突發(fā)性 a. bursty b. random c. header 答案：a30． 傳輸時(shí)延a. destination address b. transmission delay c. return signal答案：b31． 中間交換設(shè)備a. given maximum b. intermediate switching equipment c. storeandforward manner答案：b32． 子網(wǎng)a. header b. subnet c. busty答案：b33. 公眾電信網(wǎng)a. public telemunication network b. intermediate switching nodec. circuit switched network答案：aa. fullduplex b. halfduplex c. external call答案：b35. 端局a. toll center b. end office c. tandem switch答案：b36. 外部呼叫a. external call b. data traffic c. toll center答案：a37. 鏈路a. trunk b. link c. route答案：b38. 交換節(jié)點(diǎn)a. intermediate switching node b. voicefrequency circuitc. switching node答案：c39. 音頻電路a. telephone subscriber b. voicefrequency circuit c. two wire connection答案：b40. 拓?fù)鋋. internodes b. topology c. route答案：b41. 二線連接a. data traffic b. end office c. two wire connection答案：c42. 數(shù)據(jù)流量a. data traffic b. tandem switch c. toll center答案：a43. 全球通信a. interface equipment b. global munication c. munication carriers答案：b44. 脈碼調(diào)制a. pulse code modulation b. voice encoding c. open network答案：a45. 接口設(shè)備a. switching equipment b. transmission medium c. interface equipment答案：c46. 綜合業(yè)務(wù)數(shù)字網(wǎng)a) endtoend digital connectivity b. international organization for standardizationc. integrated services digital network答案：c 47. 通信載體a. munication carriers b. transmission medium c. interface equipment答案：a48. 系統(tǒng)結(jié)構(gòu) a. infrastructure c. flexibility d. basic access答案：a a. cellular switch b. cellular mobile telephone c. cellular site 答案：ba. data transmission b. transmission error c. error flag答案：aa. space level b. logical level c. mark level答案： ca. intersymbol space b. serial interface c. receiver timing答案：ca. transmission error b. obvious disadvantage c. error flag答案：b 54. 起始位a. start bit b. stop bit c. parity bit答案：a55. 空號電平a. mark level b. space level c. the idle state答案：b56. 控制比特a. binary data b. local clock c. control bit答案：c57. 串行接口a. data stream b. CRT terminal c. serial interface答案：c58. 發(fā)送器和接收器a. transmitter and receiver b. receiver timing c. duration of T seconds答案：a59. 二進(jìn)制數(shù)據(jù)a. binary data b. data stream c. data transmission答案：a60. 高速電子開關(guān)a. the voice channel b. the repetition rate c. a highspeed switch答案：c 1． digital munication b. 公共通信載體 答案：c 2． voice encoding techniques b. 脈沖 c. 脈沖編碼調(diào)制答案：a3． basic access signaling rate b. 基本接入信令速率 c.