通信与信息工程专业英语教程.docx

通信与信息工程专业英语教程

第一篇：通信与信息工程专业英语教程数据通信datacommunications以数字形式存储storedindigitalformDatum的复数dataSpectrum的复数spectra远程终端remoteterminal外围设备peripheralequipment串行serial,并行parallel时钟周期thetimeofasignalclockpulse星形拓扑startopolologies单向unidirectional有线电视行业cabletelevisionindustry公共的杆状物上放置天线Palaceanantennaontopofalargeutilitypole供一个区域共享locallysharedthesignal主天线masterantenna分发到一个大的区域Bedistributedoveralargearea光馈链接opticalfeederlinks频分复用frequencypisionmultiplexing频分多址frequencypisionmultipleaccess单向树状结构unidirectionaltree对电缆中的信号衰减进行补偿Compensatefortheattenuationofthecablesignal光纤同轴混合网HFC=hybridfiber/coaxial视频点播VOD=videoondemand分组交换有线网络packet-switchedwirelessnetwork频率大约在…….Frequenciesthatrangefromapproximately….预加重网络preemphasisnetwork去加重网络deemphasisnetwork调频器FMdeviator检波器detector，混频器mixer鉴频器discriminator，晶振crystaloscillator向上变频up-convertedthefrequenciesto…幅频特性amplitude-versus-frequencycharacteristics卫星载荷技术satellitepayloadtechnology面向公众tothepublic同步卫星geostationarysatellite蜂窝移动电话cellularmobilephone多点波束覆盖技术multi-spot-beamcoverage视线传播line-of-sightpropagation平方反比定律inversesquarelaw在相同频率，相同时间，相同波束或极化上传输transmitonthesamefrequency,atthesametimeandinthesamebeamorpolarization跳频序列frequencyhoppigsequence扩频序列spreadingsequence互调失真IMD=intermodulationdistortion多址通信有三种方式：频分多址，时分多址，码分多址multi-accesscommunicationssystemsincludethethreefamiliarmethods:FDMA,TDMA,andCDMACDMA网络容量不是无限的，因为在一些点上信道会过载，原因是占用它的用户的自干扰ThecapacityofaCDMAnetworkisnotunlimited,becauseatsomepointthechannelbecomesoverloadedbyself-interferencefromthemultipleuserswhooccupyit更关键的功率控制，因为提升一个载波的功率对其他载波而言，噪声电平会相应增加Furthermore,powerlevelcontroliscritical.becauseagivenCDMAcarrierthatiselevatedinpowerwillraisethenoiselevelforallotherscarriersbyalikeamount赤道equator，上行电路uplink以某个数量级byanorderofmagnitude近赤道轨道equatorialorbitAP=AssociatedpressUPI=unitedpressinternationalDTE=dataterminalequipmentHFC=hybridfiber/coaxialFDM=frequencypisionmultiplexingTDMA=timepisionmultipleaccessGPS=globalpositioningsystemGPRS=generalpacketradioserviceGSM=globalsystemformobile