电子信息专业英语.pdf
.实用文档.第三单元 1.Use of custom gate array logic,application specific integrated circuits(ASICs),ball grid arrays(BGAs),multichip modules(MUMs),and digital devices operating in the subnanosecond range present new and challenging opportunities for EMC engineers.定制门阵列逻辑、专用集成电路、球栅阵列、多芯片模块和亚纳米数字器件的使用为兼容工程师提供了新的挑战机遇。2.A resistor at high frequency acts like a series combination with the resistor in parallel with a capacitor.A capacitor at high frequency acts like an inductor and resistor in resistor in series combination with the capacitor plates.工作在高频的电阻表现为电感和并联的电阻、电容之间的级联。工作在高频的电容、电阻、电感的级联。9.在数字系统中，串扰是非常普遍的。在芯片上，印制电路板上，芯片封装上和连接电缆上都可能出现串扰。In digital designs the occurrence of crosstalk is very widespread.Crosstalk will occur on the chip,on the PCB board,on the connectors,on the chip package,and on the connector cables.10.许多系统工作在高频上，导体在这些频率上不再仅仅表现为导线，而是展现出高频效应并表现为传输线。如果没有正确处理这些传输线，就可能在无意中破坏了系统时序。.实用文档.Many systems operate at high frequencies at which conductors no longer behave as simple wires,but instead exhibit high-frequency effects and behave as transmission lines.If these transmission lines are not handled properly,they can unintentionally ruin system timing.第四单元 1.The available spectrum bandwidth 不同的无线射频链路以不同的方式共用频谱宽度。这些共用方式称为“多址模式。“频分多址(FDMA)“时分多址(TDMA)“码分多址(CDMA)“空分多址(SDMA)是四种主要的多址模式。7.在频分多址和时分多址系统中，一旦信道(频率或时隙)分配给用户，该信道在非活动期间也不能被利用。In FDMA and TDMA systems once a channel(frequency and/or tine slot)is allocated to user,that channel cannot be used during nonactivity periods.8.“蜂窝概念是由贝尔实验室创造的。1983 年 10 月，在芝加哥出现了第一个商用模拟语音系统。The cellular concept was invented by Bell Laboratories and the first commercial analog voice system was introduced in Chicago in October 1983.9.第三代系统的目的在于为用户提供一个语音、数据、多媒体和视频效劳的无缝网络，而不管用户在网络中的什么位置。.实用文档.The third-generation systems aim to provide a seamless network that can provide users voice,data,multimedia,and video services regardless of their location on the network.
