全套电子课件：通信工程专业英语

1、通信工程专业英语Specialized English 一、专业英语简介 专业英语（Specialized English）,又称科技英语( English for Science and Technology) ,它把英语和专业知识紧密结合起来,用专业语言来说明客观存在的事物或事实。第一部分 专业英语基础知识 1.专业英语的三大特性专业性：体现在它的特殊专业内容和特殊专业词汇上FTTC (fiber to the curb)Active optical network (AON)有源光网络脉冲编码调制第一部分 专业英语基础知识 circuit周围，巡回，绕行电路bus公共汽车总线，母线Pul

2、se-code modulation (PCM)Bit-error Rate光纤到路边误码率灵活性：体现在句子结构和词性的使用上。如英语中的动词有的表示动作，有的表示相对静止的状态。（1）TV differs from radio in that it sends and receives pictures.电视与无线电的区别在于电视能够发送和接收图像。(表示状态)（2）These two RF signals are arranged to differ by a constant frequency.这两个射频信号用于找出一个固定频率。（表示动作）专业英语基础知识 简明性：用尽可能少的单词

3、来清晰地表达原意专业英语基础知识 过去分词短语可以取代被动语态关系从句，现在分词可以取代主动语态关系从句，如 In Britain electricity energy generated in power station is fed to the national Grid.不定式短语用以替换表示目的、功能的从句，如 The function of a fuse is to protect a circuit.常使用动词或名词演化成的形容词合成新词多名词性词组多缩写使用频繁长句多在说明书、手册中广泛使用祈使语句2.专业英语有如下显著特点：专业英语基础知识 用虚拟语气表达假设或建议常用It句

4、型结构被动语态使用频繁Unit 1：第二部分 通信技术 The Evolution of Communication Theories通信理论的发展相关背景知识通信系统（Communication system）：噪声Noise信宿Destination发送设备Transmitter接收设备ReceiverSignal信源Information source信道ChannelSignalNEW WORDS AND PHRASES purport v. 声称，意味着semiotics n. 记号语言学 sociometric n. 社会测量 socio- : 社会的,社会学的proliferat

5、ion n. 繁殖，增殖 proliferate v. theorem n. 定理，法则 predictability n. 可预言 predict v. monotonically adv. 单调地，无变化地 mono- :单一 channel n. 信道，频道 aberration n. 失常,误差, 偏差,畸变,色差; 象差noise n. 杂音，干扰，噪声 premium n. 额外费用, 奖金, 佣金, 保险费 adj. 特级的recipient n. 接收者,信息接受器 For many years communications in organizations have been

6、 examined in terms of transmission and efficiency in a variety of ways. However the work of Shannon and Weaver with their communication transmission model provided a basis for much of subsequent thinking in the way communications were analyzed.in terms of :根据, 按照, 用.的话, 在.方面Transmission:传输 efficienc

7、y:有效性 subsequent:后来的多年以来，从传输和有效性的角度来说，已经用多种方式调查过各种组织机构中的通信，然而Shannon和Weaver的通信模型为后来分析通信方式的许多见解提供了基础。TEXT In essence it is a data transmission model and does not purport to be a communication theory in which wider considerations, such as language, semiotics, sociometric and culture aspects must be in

8、cluded in order to analyze organizational communications.In essence：本质上，其实 purport：宣称，声称semiotics：记号语言 sociometric：社会测量本质上，它是一个数据传输模型，而不是宣称一个通信理论：在该理论中，为了分析组织通信，它一定要包括更广泛的考虑因素，诸如语言、记号语言、社会测量和文化等。 The process model of Shannon and further developed with Weaver, see Fig.1, is essentially a model of dat

9、a transmission. It is based on an information theory, which was developed by Hartley and Nyquist and incorporated into Shannons channel capacity theorem. information theory：信息论essentially:本质上, 本来based on:基于incorporate：合并 Information theory is based on the predictability of messages, resulting in the

10、 information content of a message monotonically decreasing with increasing probability of its occurrence. predictability：可预言 predict predictable information content ：负平均信息量monotonically：单调地probability ：几率, 概率，可能性occurrence：发生, 出现: information content of a message 信息量: probability of occurrence 发生概率T

11、he channel capacity theorem relates the maximum rate of transmission , expressed in terms of binary bits per second for a digital communication channel, to those resources used to transport the signals and the environment for the transmission.relateto：显示出与的关系resource： 消息来源,信道容量准则显示出最大传输速率与传送信号的资源及传输

12、环境之间的关系，对数字通信信道，最大传输速率以每秒的二进制位表示。 Berlo in his examination of the elements involved in communication said, “One must understand humans behaviors in order to understand communication”. He constructed a model of interpersonal communication that contains four components that affect the fidelity of comm

13、unication. elements ：要素, 成分, 元件 interpersonal ：人与人之间的fidelity ：逼真度, 保真度, 重现精度小 结通信类专业英语的三大特性与普通英语相比专业英语的特点 Introduction to Optical Fiber Communication光通信之父高锟1966年7月，英籍华人高锟发表了著名文章用于光频的光纤表面波导，从理论上证明了用光纤作为传输媒体以实现光通信的可能性。1.词汇和句型：词汇是语言的基础，科技英语中的词汇可分为四类:普通词汇、专业词汇、专业缩写词汇和转意词汇。普通词汇：这些词汇在科技英语中的意义和用法与在普通英语中基本

14、是一致的。 冠词、动词、副词、介词、形容词、数词、连接词、名词、代词二、科技英语中的几个关键问题 专业英语基础知识 专业词汇：在通信技术中常用的专业词汇专业英语基础知识 electron、amplifier、electromagnetic wave、transceiver、frequency、parameter. 专业缩写词汇：在通信技术中常用的专业缩写词汇PCM pulse code modulationSSB single side band LASER light amplification by stimulated emission of radiation LAN local ar

15、ea networkWWW world wide webFig. FigureDSP digital signal processing转义词汇：从普通词汇中借用、移植过来的，并赋予它们不同于普通应用时的专门含义。专业英语基础知识 转意词 普通含义 专业含义current 水流，气流，趋势，当前的 电流 circuit 周围，巡回，绕行 电路carrier 运载工具 载波，载流子modulator 调节者 调制器flip-flop 翻跟斗 触发器Specialized English 通信工程专业英语ListeningSpeakingWritingTranslatingReading ：译文必

16、须通顺流畅，符合语言规范，不应有文理不通、逐词死译和生硬晦涩等现象。 ：译文必须符合原意，准确地、完整地、科学地表达原文的内容，不得有任何篡改。通顺（Smooth）不是用译者的意思来代替原文的意思第一部分 专业英语基础知识 专业英语的翻译（Translating）忠实（True）1.翻译的标准翻译：用一种语言把另一种语言所表达的思想内容准确而又完整地再现的语言活动。把原文意思用译语准确无误地传达出来EnglishChinese硬译死译胡译句子结构上有差异词汇上很少对等直译：基本上保留原文的表达形式及内容，不做大的改动，同时译出的文字又明白易懂；意译：在正确理解原意的基础上，重新遣词造句，把原文

17、的意思用通顺的汉语表达出来。专业英语的翻译照译：基本上保留原文的结构形式，语序上未作大的变动；保留原文词语的字面意思，未加引伸和转换。2.翻译方法Computers are of great help to our work. 计算机对我们的工作有很大帮助。Compounds are composed of elements. 化合物是由元素构成的。专业英语的翻译转换：词义引伸和词性转换（意义上的转换）；语序的变动，句子结构和句子表达方式的转换（形式上的转换）。The miniature receiving antenna was developed as an alternative to

18、that larger one. 这种小型接收天线是为取代那种大型接收天线而研制的。 （译文把原文中的名词转换成了动词）The reliability can be further improved by using error-detecting and error-correcting codes. 利用检错和纠错编码能进一步提高可靠性。（被动语态转译为主动语态）专业英语的翻译省略：根据汉语语法的修辞习惯，将原文中的某些词语略去不译。（如英语中的冠词、代词和连词）Air is a fluid but not a liquid. 空气是流体, 不是液体。（省略冠词）If you know t

19、he frequency, you can find the wave length. 如果知道频率，就能求出波长。（泛指的人称代词you可省略不译）专业英语的翻译增补：按照汉语语言习惯，在译文中适当添加原文中所没有的词语，以更明确的表达原文的含义和满足汉语语法的修辞需要。This is what we must resolve at first. 这是我们必须首先解决的问题。(增补宾语)专业英语的翻译Unit 2：第二部分 通信技术 Digital Communication System数字通信系统相关背景知识NEW WORDS AND PHRASES immuneadj.免除的,不受影响

20、的,可避免的threshold n.门槛,门限intertlace v.使交织,使交错hierarchy n.等级,体系,系列crosstalkn.串话feasibleadj.可行的,行得通的elimination n.消除,排除,淘汰intervaln间隔时间supervision n.监督,监管overvoltage n.超压,过电压suppressv.抑制nonlinearly ad.非线性地resolution n.分析,分辨polarityn.极性 The use of digital methods for the transmission of analog signals is

21、 becoming increasingly common in telecommunication systems. There are two major reasons for this. digital :数字的, 数位的analog:模拟（的） telecommunication电讯, 长途通讯在通信系统中使用数字方式来传输模拟信号正变得越来越普遍，这主要由两种原因引起。TEXT First, if digital rather than analog signals are transmitted, then the system remains nearly immune to

22、noise as long as it is below a threshold level.rather than ：而不是immune to ：可避免的,不受影响的as long as ：只要, 在.的时候threshold level：门限电平第一,如果传输的是数字信号而不是模拟信号,则只要噪声电平低于门限电平,系统就几乎不受影响。 This is due to the fact that for long-distance transmission the digital signal can be regenerated at each repeater, creating a ne

23、w, noise-free signal. Thus, noise does not accumulate as it would in a comparable analog system. due to ：由于, 应归于regenerate：再生，重建repeater：中继器，再生器accumulate：积累这是因为：对于长距离传输，数字信号可以在再生器中重新生成，从而产生一个新的、无噪声的信号，因此噪声不会像在模拟系统中那样积累。Second, the components of a digital system lend themselves well to integrated im

24、plementation using large-scale-integrated (LSI) circuits. component：组成，成分 lend oneself to：适合于implementation：落实，实施，实际应用，执行, 履行; large-scale-integrated (LSI) circuits：大规模集成电路第二，数字系统的组成使其适合于采用大规模集成电路实际应用场合。Even in such a digital transmission system, however, many signals which are being processed are u

25、sually analog in nature. There analog signals need therefore to be converted into digital format. in nature：实际上, 本质上convert into：使转变（转换）成. format ：形式, 格式, 版式 然而，即使在这样的数字传输系统中，所处理的许多信号通常在本质上是模拟的。因此，需要将这些模拟信号转化为数字形式。 There are various modulation schemes to accomplish this, including pulse-width modula

26、tion (PWM), pulse amplitude modulation (PAM),and pulse code modulation (PCM) . PCM is currently the most commonly used modulation system in digital telecommunication systems. pulse-width modulation (PWM):脉宽调制pulse amplitude modulation (PAM) :脉幅调制pulse code modulation (PCM) :脉码调制有多种调制手段以实现这种转换,包括脉宽调制

27、、脉幅调制以及脉码调制. PCM是当前数字通信系统中最普通的调制手段。The PCM signal is generated by sampling, quantizing, and coding an analog signal. The result is a stream of binary digits (bits), that is, an alternation of high and low voltage levels in the signal. This stream can then be applied, frequency modulation. sampling ：

28、取样 quantizing：量化 coding：编码 alternation：交替, 变换; 间隔PCM信号是通过对模拟信号取样、量化、编码产生的。结果是产生一系列的二进制比特流，即交替的高低电平。 The process of sampling an analog voltage V (t) consists of developing a pulse train in which the amplitude of the nth pulse equals the amplitude of V(t) at t= nT. consists of ：由.组成pulse train ：脉冲串amp

29、litude：幅值，振幅，幅度对模拟电压V(t)采样过程包括生成一个脉冲串,在这个脉冲串中,第n个脉冲的幅度等于V(t)在t=nT时的幅值。 In order for the pulse train to represent uniquely the information contained in V(t), the sampling rate fc=1/T must be at least twice as large as the highest frequency component in the spectrum of V(t), the amplitudes of the puls

30、es in the sampled signal are then quantized and converted into a set of bits, called a digital word. sampling rate:抽样（频）率 spectrum：谱，光谱，频谱为了让脉冲序列唯一表示V(t)包含的信息，抽样频率fc=1/T至少为V(t)频谱中最高频率成分的2倍，然后对抽样信号中的脉冲幅值进行量化并转化为一系列的比特，称作码字。 The transmission of digital words in a practical PCM telecommunication system

31、 often utilizes time-division multiplexing (TDM). In a TDM system, the digital words taken from several channels are transmitted interlaced over the same line. time-division multiplexing (TDM) ：时分复用interlaced：交织的,交错的在实际的PCM长途通信系统中经常利用时分复用方式来传输码字。在TDM系统中，来自几个信道的码字交错着在一条线路上传输。In voice-frequency (telep

32、hone) systems, usually 24 or 32 voice channels are thus multiplexed onto a single pair of wires. voice-frequency (telephone) systems：音频（电话）系统multiplex：复用在音频（电话）系统中，通常将24或32路话路复用到一对线路中传输。The International Telegraph and Telephone Consultative Committee (CCITT) had recommended two main architectures (“

33、hierarchies”), which now many nationwide PCM transmission network use. CCITT ：国际电话与电报顾问委员会architectures ：体系机构hierarchy ：体系制, 系统，数据层次nationwide ：全国性的CCITT推介了两种主要的体系，现在许多全国的PCM传输网络都在采用。The first one, shown schematically in Fig.1, has been adopted mostly in Europe, Africa, Australia, and South America.

34、 In this system, the input multiplexers (MUX) interleave 32 digital words. Of these, 30 words represent the signal amplitudes in 30 voice channels, while the remaining two time slots contain signaling and synchronization information. schematically ：示意性地 multiplexers ：多路(复用)器 interleave：使交织替, 插time s

35、lots ：时间的空当，时隙 synchronization：同步在这种体系中，输入复用器将32路信息码交插在一起。其中30路码字代表30路语音信道，其余2路时隙包含随路信令和同步码。The second hierarchy, used mainly in the United States, Canada, and Japan, is illustrated in Fig. 2. In this system, 24 voice channels are multiplexed at the input section. illustrate：举例说明, 图解 multiplex：多路传输，

36、多路复用第二种体系由图2所示，主要用在美国、加拿大和日本。在这种系统中，24路语音信号在输入端复用在一起。There are two main tasks performed in a digital telecommunication system: transmission and switching. Transmission involves sending the digitally coded voice signal from one 1ocation to another, while switching consists of establishing the desired

37、 connection between two voice channels which carry digital signals. perform ：履行, 执行，完成任务 switching：交换1ocation：地点传输包括把数字编码的语音信号从一个地方发送到另一个地方，而交换包括建立两个话音信道的有效连接，这两个信道是（用来）承载数字信号的。 The unit which performs the pulse code modulation and demodulation of the signals in a digital transmission system is call

38、ed a coder-decoder, or, in abbreviated form, a codec. demodulation ：解调, 反调制, 检波coder-decoder ：编/解码器abbreviated ：省略的, 缩写的 codec ：数字信号编解码器在数字传输系统中，对信号进行脉码调制和解调的单元被称作编/解码器，或缩写为codec.In early digital systems, the switching was done in an analog form, using such analog devices as the electromechanical cr

39、ossbar mechanism. electromechanical ：电动机械的,机电的 crossbar mechanism ：纵横机械组装在早期的数字系统中，通过使用像纵横交换机这样的模拟设备，在模拟形式中进行交换.Then, the analog voice signal channels were time-multiplexed into groups of 24 or 30 channels. Each group was next converted into digital form by a single high speed codec. time-multiplexe

40、d ：时分复用然后，将单个的模拟语音话路时分复用为24路或30路的组合。接下来，通过一个高速的数字信号编解码器将每一组合转化为数字形式。This arrangement resulted in some savings in terms of the number of components; however, the design of the shared codec with a sufficiently low line-to-line crosstalk and noise, as well as the required high speed in a fully integrat

41、ed form represented a very difficult design problem. line-to-line crosstalk ：线间串话integrated ：集成的这种排列导致了器件数量的一些减少，但是，具有足够低的线间串话和噪声,同时又具有所需很高速度的全集成(各路)共用编解码器的设计代表了一个很难的设计问题。In addition, any failure of the codec resulted in the loss of service to all lines serviced by that unit. Also, the system requir

42、ed a large number of analog switches, which were bulky and slow. failure ：故障bulky：庞大的, 体积大的, 笨重的, 占地方的此外，编解码器的任何故障都会导致这个单元所服务的所有线路丢失其所需的服务。而且，这种系统需要大量笨重且低速的模拟转换器。Finally, the analog multiplexing needed was more difficult to perform and less flexible than digital multiplexing would have been.analog m

43、ultiplexing ：模拟多路复用flexible ：灵活的, 柔软的digital multiplexing ：数字多路复用最终，所需的模拟多路复用与数字多路复用相比,在实现上更为困难,灵活性亦更差With the recent availability of low-cost and high-performance integrated circuits, it became feasible to allocate one codec to each voice channel, rather than to a group of channels. availability ：可

44、用性, 有效性, 实用性high-performance：高性能integrated circuits ：集成电路allocate：分配，配给，分派随着近来低成本、高性能集成电路的实用化，可以为每一路语音信道分配一个编解码器，而不是一组信道使用一个编解码器 。The voice signal in each channel is thus first digitized, and the subsequent switching and multiplexing are performed by digital systems which can use low-cost digital lo

45、gic and memory circuits. digitize ：将（例如数据）数字化subsequent ：后来的, 并发的，随后的因此，首先将每个信道中的语音信号数字化，随后的交换和复用是由数字系统完成的，数字系统可以使用廉价的数字逻辑电路和存储电路。Such a “per-channel codec” system results in a considerable reduction of crosstalk and noise. Also, there is a significant saving in size and cost, due to the elimination

46、 of most of the bulky and expensive electromechanical components. considerable ：相当大(或多)的, 相当可观的significant ：有意义的, 重大的, 重要的elimination ：排除, 除去, 消除bulky ：大的, 容量大的, 体积大的每信道一个编解码器的系统，显著减少了串话和噪声的影响 。此外，由于除去了使用体积庞大且贵重的电动机械的部件而显著节省了空间和成本。The standard sampling rate fc recommended by the CCITT for the usual

47、3003400 Hz voice channel is 8000Hz. recommended ：被推荐的sampling rate ：取样频率对于通常的3003400 Hz 的语音信道，CCITT推荐的标准取样频率为8000Hz。In the per-channel codec system, the analog signal is thus sampled at intervals of 1/8000Hz=1.2510-4S=125s, and the amplitude of the sample is converted into an eight-bit digital word

48、is then transmitted serially to the multiplexer. at intervals of ：相隔, 每隔serially ：连续地在每信道一个编解码器的系统，每隔125s对模拟信号取样一次，将样值的幅度转化成一个8比特的码字，然后再连续的传输给复用器。The 125-s-long time interval available for the conversion is called a erval ：时间间隔frame ：帧将这个用来转换的125s长的时间间隔称作一帧。The digital multiplexer places al

49、l the bits corresponding to one sample of each of 24 or 30 channels (depending on the hierarchy used) into a single frame, and transmits the resulting serial bit stream. 数字复用器把对应于24路或30路各路样值的全部比特放在一个帧中，然后传输结果串行比特流。To mark the beginning and the end of each frame at the receiver, some identifying sign

50、al should be added to the transmitted bit steam. mark ：做标记于, 标志identifying signal ：识别信号为了在接收机处能够对每一帧的帧头和帧尾进行标识，应该在传输的比特流中加入一些识别信号。For example, in the 24-channel eight-bit PCM system called D2 developed by AT&T, an additional bit is appended to the bits of each frame. appended to ：附加，添加，贴上例如，在被AT&T称作

51、D2 的24信道8比特PCM系统中，给每一帧中附加了一个比特。Thus, a frame in the D2 system contains 248+1=193 bits. Hence, the data rate of the transmitted signal is 193 bits per 125s, which corresponds to 1.544106bit/erval ：时间间隔frame ：帧从而，在D2系统中，每一帧包含248+1=193 bits 。因此，所传输信号的数据率为193 bits/125s,对应 1.544106bit/s的速率。In the tr

52、ansmit direction, the subscribed line is connected to the subscriber-line interface circuit (SLIC). The SLIC performs the two-to-four wire conversion, the battery feed, the line supervision, and also provides ringing access and over voltage protection. SLIC ：subscriber-line interface circuit 用户线接口电路

53、battery feed ：远端供电line supervision ：线路监测ringing access ：铃流接入over voltage protection：过压保护The signal then passes through the transmit filter, which limits its spectrum to (approximately) 3400Hz.The transmit filter thus removes the part of the spectrum which extends over 4kHz,and thus makes it possible

54、 to sample the signal at an 8 kHz rate without introducing aliasing. transmit filter：发送滤波器approximately：近似地, 大约aliasing：混淆现象信号接着通过发送滤波器，发送滤波器将信号频谱限制在3400Hz附近，因此去掉了超出4kHz的频谱，从而使得以8 kHz 的频率对信号抽样而不出现混频成为可能。 In addition, the low-frequency portion (below 300Hz)of the spectrum is also suppressed by the tr

55、ansmit filter, to prevent power-line frequency (50 or 60 Hz) noise from being transmitted. low-frequency portion ：低频部分suppressed ：抑制, 压制 power-line frequency ：传输线频率prevent. from：使.不做某事, 阻止.做某事此外，频谱的低频部分（300Hz以下）也被发送滤波器抑制掉，以阻止传输线频率噪声。 The filtered signal, now band limited to the 300 to 3400 Hz range,

56、 is then sampled at an 8 kHz rate, and then converted (encoded) into eight-bit PCM data. This conversion is performed nonlinearly; that is, the resolution of the resulting digital signal is finer for small signals than for large ones. nonlinearly ：非线性地, 非直线(型)地resolution ：分辨率, 清晰度经过滤波的信号，频带被限制在300 t

57、o 3400 Hz 范围内，然后以8 kHz 的频率对其进行抽样，转换（编码）为8bit的PCM数据。这种转换是非线性的，即对小信号其生产的数字信号的分辨率要优于大信号。 The output of the nonlinear A/D converter is a specially coded eight-bit digital word. The first bit indicates the sign of the input x, with“1”representing positive and“0”negative polarity. The next seven bits prov

58、ide the amplitude value of the signal.A/D converter ：模拟/数字转换器positive ：正的;阳性的 negative：负的;阴极的;非线性模/数转换器输出经过特殊编码的8bit码字，其中第一个bit表示输入x的符号，1表示正极性，0表示负极性，后7位bit表示信号的幅值。 Returning to the block diagram of Fig.4, the digital output of the encoder is then time-division multiplexed with the outputs from the

59、other lines, and the resulting bit stream is transmitted over the channel.block diagram ：方框图，结构图time-division multiplex：时分复用 positive ：正的;阳性的 negative：负的;阴极的;编码器的数字输出与其他线路的输出通过时分复用，产生的bit流在信道中传输。 At the receiver side, the incoming data are demultiplexed, that is, distributed among the various channe

60、ls, and decoded (i.e., D/A converted). The analog output is then sampled-and-held, and passed through the receive filter. incoming data ：输入数据 demultiplex ：解复用，分离 D/A convert ：数/模转换 negative：负的;阴极的; sampled-and-held ： 在接收端，对输入数据进行解复用，即在各个通路间分配并解码（数/模转换 ）。The latter is a low-pass smoothing filter, whi