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基础电子学电子学衍生于对电力的研究和应用，是工程学和应用物理学的领域。
电力涉及力的产生，传输与使用金属导体。
电子学利用电子不同的运动方式及通过供气材料，如硅与锗等半导体，其他设备如太阳能电池，LED，微波激射器，激光及微波管等实现。
电子学应用于包括广播、雷达、电视、卫星系统传输，导航辅助设备系统，控制系统，空间探测设备，微型设备如电子表，许多电气设备和电脑等方面。
1.电子学的开端电子学的历史始于20世纪，包括三个关键元素：真空管，晶体管和集成电路。
19世纪早期是理论和发明取得重大发展的时代。
发现了红外线和紫外线。
道尔顿在1808年提出了原子理论。
在1840年之前就发现了热电效应、电解效应和光电效应。
20年之间相继产生了工作在低压下的放电管，辉光放电，新型电池及早期的扩音器。
因此，在1800—1875年之间，发现了基本的物理现象，电话，留声机，麦克风及扬声器等在实际应用中达到了极致。
至于19世纪末期，无线电报，磁记录，阴极射线示波器等都被发明了。
20世纪早期也见证了现代电子技术的开端。
1880年爱迪生发明了白炽灯成为现代电子领域的历史先驱者。
他发现有微弱的电流从加热的灯丝流向真空管内附着的金属板。
这就是众所周知的“爱迪生效应”。
如果使用了一个非电器的热源，注意到电池仅是必要的用来加热灯丝使电子移动。
1904年，约翰利用爱迪生效应发明了二极管，李.德.佛列思特紧接着在1906年发明了三极管。
这些真空管设备使电子能源控制的放大及传输成为可能。
20世纪初真空管的引入使现代电子学快速成长。
采用真空管让信号的控制成为可能，这是早期的电报电话电路不可能实现的，也是早期用高压电火花产生无线电波的发射机所不能实现的。
电子管首先应用于无线通信。
Guglielmo Marconi于1896年开辟了无线电报的发展，于1901年实现了远距离广播交流。
早期的收音机包括了无线电报（摩尔斯电码信号传输）或收音机电话（语音留言）。
通信工程专业英语Revised at 16:25 am on June 10, 2021I hope tomorrow will definitely be better一、汉译英1、时分多址：TDMA Time Division Multiple Address/ Time Division Multiple Access2、通用无线分组业务：GPRSGeneral Packet Radio Service3、国际电报电话咨询委员会：CCITT4、同步数字体系：SDH Synchronous Digital Hierarchy 同步数字序列5、跳频扩频：FHSS frequency hopping spread spectrum6、同步转移模块：STM synchronous transfer module7、综合业务数字网：ISDNIntegrated Services Digital Network 8、城域网：MAN Metropolitan Area Network9、传输控制协议/互联网协议：TCP/IP Transmission ControlProtocol/Internet Protocol10、服务质量：QOS Quality of Service11、中继线：trunk line12、传输速率：transmission rate13、网络管理：network management14、帧结构：frame structure15、移动手机：Mobile Phone 手机Handset16、蜂窝交换机：Cellular switches 电池开关cell switchcell 蜂房17、天线：Antenna18、微处理器：microprocessor19、国际漫游：International roaming20、短消息：short message21、信噪比：SNRSignal to Noise Ratio22、数字通信：Digital communication23、系统容量：system capacity24、蜂窝网：cell networkcellular network Honeycomb nets 25、越区切换：Handover26、互联网：internet27、调制解调器：modem28、频谱：spectrum29、鼠标：Mouse30、电子邮件：electronic mail E-mail31、子网：subnet32、软件无线电：software defined radios33、网络资源：network resources二、英译汉1、mobile communication：移动通信2、Computer user：计算机用户3、Frame format：帧格式4、WLAN：wireless local area network 无线局域网络5、Communication protocol：通信协议6、Transmission quality：传输质量7、Remote terminal：远程终端8、International standard：国际标准9、GSM：全球移动通信系统Global System for Mobile Communications10、CDMA：码分多址Code Division Multiple Access11、ITU：国际电信联盟International Telecommunication Union12、PCM：pulse code modulation 脉冲编码调制13、WDM：波分复用Wavelength Division Multiplex14、FCC：联邦通信委员会Federal communications commission 15、PSTN：公用电话交换网Public Switched Telephone Network 16、NNI：网络节点借口Network Node Interface17、：万维网World Wide Web18、VOD：视频点播Video-On-Demand19、VLR：访问位置寄存器Visitor Location Register20、MSC：移动交换中心Mobile Switching Centre21、HLR：原籍位置寄存器Home Location Register22、VLSI：超大规模集成电路Very Large Scale Integrated Circuits23、Bluetooth technology：蓝牙技术24、Matched filter：匹配滤波器25、ADSL：非对称数字用户环路Asymmetrical Digital Subscriber Loop 非对称数字用户线路Asymmetric Digital Subscriber Line26、GPS：全球定位系统Global Position System27、ATM：异步传输模式Asynchronous Transfer Mode三、汉译英1、脉冲编码调制PCM依赖于三个独立的操作：抽样、量化和编码;PCM is dependent on three separate operations: sampling, quantizing and coding;2、像TCP和IP那样的协议已经被设计出来,当然,它们还需要被更新和维持;Protocols like TCP and IP have already been designed,of course,but they need to beupdated and maintained;3、码分多址是一种前景广阔的宽带数字工作系统;One form of digital wide band operation which has good future potential is CDMA;4、互联网是可提供很多网络资源的最大的信息库;The internet is the largest repository of information which can provide very largenetwork resources.5、开发蜂窝式移动电话系统并将其在许多城市中推广应用的原因之一是传统的移动电话系统存在容量有限、服务性能差、频谱利用率低的缺点;One of many reasons for developing a cellular mobile telephone system and deploying it in many cities is the operational limitations of conventional mobile telephone system;limited servile capability,poor service performance,and inefficient frequency spectrum utilization.6、来自发端借口不见的定时新号被加到数据调制解调器上,以使计算机与数传机同步;在接收端,从数据流中取出同步脉冲式计算机同步;Timing signals from the interface assembly at the transmitter are applied to the data modem to synchronize the computer and the data set. At the receivers synchronizationpulses are derived from the data stream to synchronize the computer.7、我们正处于通信网络革命的开始,越来越大的容量需求,各种各样的应用,以及服务质量正在对光网络提出巨大的需求;We are at the beginning of a revolution in communications networks, where increasing capacity, variety of applications, and quality of service are placing enormous demands on the optical network.8、目前在欧洲正在开发第三代移动通信系统,其目的是要综合第二代系统的所有不同业务并覆盖更广泛的业务话音、数据、视频、多媒体范围,而且还要与固定电话网络的技术发展保持一致和兼容;The third generation mobile communication system currently being developed in Europe, intended to integrate all the different services of the second generation system andcover a much wider range of broadband services Voice、data、video、multimediaconsistent and compatible with technology developments taking place within the fixed telecommunication networks.9、在现代对多媒体的描述中,我们所具有的技术已开始向人类具有的能力迈进；通过使用计算机技术、软件和其他技术,如CD-ROM;不仅能将视频图像和音频综合在一起,而且可以与其他计算机用户进行交互工作;In the modern presentation multimedia we now have the technology that can begin to move towards an ability already held by the human beings in that by using computer, technology, software and other technology, such as CD-ROM not only can we bring together audio and visual images but interactive with other computer users.10、为弥补这些问题,要在基本结构中加入大量的高效中继线;高效中继线用于直接连接有大量的节点间通信业务量的各交换中心;通信量常常是通过网络中可用的最低层次传送的;To compensate for these problems, a large number of high usage trunks augment the basic architecture. High-usage trunks are used for direct connection between switching centers with high volumes of internodes traffic. Traffic is always routed through the lowest available level of the work.11、光纤网络的革命刚刚开始,并正快速向未来的带宽无线、可靠和低费用的在线世界发展;The revolution of optical network is just beginning, and is advancing very swiftly towarda future online world in which bandwidth is essentially unlimited、reliable and low-cost.12、实际设备通常使用8kHz的采样速率,而如果每个样值用8位码的话,则话路是由一个重复速率64kHz的脉冲流来表示;Practical equipments, however, normally use a sampling rate of 8 kHz, and if 8 digits per sample value are used the voice channel becomes represented by a stream of pulses with a repetition rate of 64 kHz.13、是由于SDH设备在这些方面的标准化,才提供了网络运营者所期望的灵活性,从而能低价高效地应付带宽方面的增长并为后十年中出现的新的用户业务作好准备;It is the standardization of these aspects of SDH equipment that will deliver the flexibility required by network operators to cost effectively manage the growth in bandwidth and provisioning of new customer services expected in the net decade.四、英译汉1、The cellular concept is defined by two features, frequency reuse and cell splitting. Frequency reuse comes into play by using radio channels on the same frequency in coverage areas that are far enough apart not to cause co-channel interference. This allows handling of simultaneous calls that exceed the theoretical spectral capacity. Cell splitting is necessary when the traffic demand on a cell has reached the maximum=m and the cell is then divided into a micro-cellular system. The shape of cell in a cellular system is always depicted as a hexagon and the cluster size can be seven, nine or twelve. 蜂窝的概念由两个特点决定,频率复用和小区分割;在相邻覆盖区域足够远的而不至于引起共用信道干扰的,通过使用同一频率的无线信道,频率再利用才起作用;这样可以出来同时出现的呼叫并超出理论频谱容量;当小区的业务需求增到最大时,就要被划分,小区就要被划分成更小的蜂窝系统区域,蜂窝系统的小区形状常被描述成六边形,一群小区数量可以是9个或12个;2、Before you can use the Internet, you must choose a way to move data between the Internet and your PC. This link may be a high-speed data communication circuits, a local area network LAN, a telephone line or a radio channel. Most likely, you will use a Modem attached to your telephone line to talk to the Internet. Naturally, the quality of your Internet connection and service, like many other things in life, is dictated by the amount of money you are willing to spend.Although all these services can well satisfy the needs of the users for information exchange, a definite requirement is needed for the users. Not only should the users know where the resources locate, but also he should know some operating commands concerned.在使用Internet之前,必须使用一种方法在呢的PC机和Internet之间传递数据,这种连接的链路可以是高速数据通道电路,局域网,电话线路或无线信道;最有可能的是,你使用Modem连到电话线上与Internet对话;当然像生活中许多其他事物一样,与Internet连接服务和质量是由你花钱的数量来决定的;虽然这些所有的服务可以很好满足用户交换信息需要,但用户仍旧需要具有特定的先决条件,用户不但要知道信息资源的位置而且要知道一些有关的操作命令;3、Packet switching achieves the benefits discussed so far and offers added features. It provides the full advantage of the dynamic allocation of the bandwidth, even when messages are long. Indeed, with packer switching, many packets of the same message may be in transmission simultaneously over consecutive links of a path from source to destination, thus achieving a ‘pipelining’ effect and reducing considerably the overall transmission delay of the message as compared to message switching. It lends to require smaller storage allocation at the intermediate switches. It also has better error characteristics and leads to more efficient error recovery procedures, as it deals with smaller entities. Needless to say, packer switching presents design problems of its own, such as the need to reorder packets of a given message that may arrive at the destination node out of sequence.分组交换除具有以上讨论的有点之外,还具有一些特点;它提供带宽动态分配的全部优势,甚至当报文很长时依然如此,由于有分组交换,一个报文的多个分组确定可以通过原点到终点通路中多个链路同时传送,因而道道“管道”传送的效应,与报文交换相比,他大大的减少了报文整体传送时延;在中间交换设备中这种方式只需要较小的存储分配区域;分组交换的误码特性较好,由于它只涉及很短的长度,因而导致更高效的纠错方式;当然,分组交换也有自身设计上的麻烦,例如,当报文无序到达目的节点时,需要重新对该报文进行分组排序;4、As more and more systems join the Internet, and as more and more forms of information can be converted to digital form, the amount of stuff available to Internet userscontinues to grow. At some points very soon after the nationwide Internet started to grow, people began to treat the Net as a community, with its own tradition and customs.随着越来越多的系统连接到互联网,越来越多的信息被转化为数字形式,互联网用户可利用的资料持续增长,在不久的将来当国内互联网的规模增加到一定程度时,人们开始把互联网当做社区对待,并且拥有自己的传统和习惯;5、Three components are involved in a basic optical fiber system: the light source, the photo detector, and the optical transmission line. The optical light source generates the optical energy which serves as the information carrier, similar to a radio wave source supplying electromagnetic energy at radio wave wavelengths as the information carrier.The optical photo detector detects the optical energy and converts it into an electrical form. The optical fiber transmission line is the equivalent of copper wires and functionas the conductor of optical energy.基本的光纤系统涉及到3个部分：光源、光检测器和光缆;光源产生的能力作为信息的载体,类似于具有电磁能的无线电波用波长作为信息载体,光检测器检测光能并将其转化为电能的形式,光缆等效于铜线具有传导光能的作用;6、The fixed telephone service is global and the interconnection varies from coaxialcable to optical fiber and satellite. The national standards are different, but with common interfaces and interface conversion, interconnection can take place. For mobilethe problem is far more complex, with the need to roam creating a need for complex networks and system. Thus in mobile the question of standards is far more crucial to success than fixed systems.The GSM system is based on a cellular communications principle which was first proposedas a concept in the 1940s by Bell System engineers in the U.S. The idea came out of the need to increase network capacity and got round the face that broadcast mobile networks, operating in densely populated areas, could be jammed by a very small number of simultaneous calls. The power of the cellular system was that it allowed frequency reuse.全球范围内的固定电话通过同轴电缆、光缆和卫星相连;尽管各国的通信标准不同,但是由于有共同的接口和接口转换设备,互连问题得以解决;对于移动通信存在漫游问题,网络和系统就比较复杂,所以移动通信的标准问题就更关键;1940年有美国贝尔系统工程师提出的蜂窝通信原理是GSM系统的基础,其思路是在人口密集的区域由于一些同时发起的呼叫导致网络拥塞,采用蜂窝系统可以增加系统的容量,蜂窝系统的优点在于频率的重复利用;7、The advantage of SDH are mainly reflected in the following:1Lower network element costs: With a common standard, compatible equipment will be available from many vendors.In a highly competitive market prices will be vary attractive. 2 Better network management: With better network management, operators will be able to mote efficientlyuse the network and provide better service. The concept of TMNTelecommunication Management Networksis under study by CCITT. Some TMN standards defining management system interfaces already Faster provisioning: If new circuits can be software defined to use existing spare bandwidth then provisioning will be mush faster. The only new connection needed will be from the customer’s premises to the nearest network access node.SDH的优点是：1、较低的网络成本：由于具有共同的标准,许多供应商提供的设备可以兼容,激烈的时长竞争可以降低成本,2、更好的网络管理：运营商有能力提供更有效的业务,电信网管标准正在由CCITT指定,定义管理接口的相关标准已经出台;3、快速准备：如果新的电路可被软件来定义,利用现有的空闲频段从用户到最近的网络节点,接入的准备工作将更快;8、If we consider binary transmission, the complete information about a particular message will always be obtained by simply detection the presence or absence of the pulse. By comparison, most other forms of transmission systems convey the message information using the shape, or level of the transmitted signal; parameters that are most easily affected by the noise and attenuation introduced by the transmission path. Consequentlythere is an inherent advantage for overcoming noisy environments by choosing digital transmission.Noise can be introduced into transmission path in many different ways; perhaps via a nearby lightning strike, the parking of a car ignition system, or the thermal low-level noise within the communication equipment itself. It is the relationship of the truesignal to the noise signal, known as the signal-to-noise ratio, which is of most interest to the communication engineer.如果进行二进制传输,通过检测脉冲的有无就可获得报文的全部信息,相比之下,其他传输系统携带信息是通过波形和信号电平,这些参数容量收到噪声和传输信道衰减的影响,因此数字通信具有克服噪声环境的内在优势;噪声可能通过不同的方式进入传输信道,附近的闪电、汽车点火系统或者通信设备内部的热噪声,通信工程师最感兴趣的是信噪比;9、Most of the subscribers on the network ate telephones. The telephone contains a transmitter and receiver for converting back and forth between analog voice and analog electrical signals. With the introduction of the digital data system, some subscribers that transmit digital signals have been incorporated into the network.网络中大多数用户都是电话机;电话机包括一个送话器和一个受话器,用料在模拟话音和模拟电信号之间进行变换;随着数字、数据系统的引入,有些传输数字信号的用户已经并入该网;。
