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1、Specialized English,通信工程专业英语,：译文必须通顺流畅，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,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
2、译：在正确理解原意的基础上，重新遣词造句，把原文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 d
3、eveloped as an alternative to 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.
4、空气是流体, 不是液体。（省略冠词） If you know the 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,N
5、EW WORDS AND PHRASES,immune adj. 免除的,不受影响的,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 crosstalk n. 串话 feasible adj. 可行的,行得通的 elimination n. 消除,排除,淘汰 interval n 间隔时间 supervision n. 监督,监管 overvoltage n. 超压,过电压 suppress v. 抑制 nonlinearly ad. 非线性地 resolution n. 分析,分辨 polarity n.
6、 极性,The use of digital methods for the transmission of analog signals is 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 tha
7、n analog signals are transmitted, then the system remains nearly immune to 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 tr
8、ansmission the digital signal can be regenerated at each repeater, creating a new, 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
9、样积累。,Second, the components of a digital system lend themselves well to integrated implementation 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 s
10、uch a digital transmission system, however, many signals which are being processed are usually 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
11、形式。,There are various modulation schemes to accomplish this, including pulse-width modulation (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 pu
12、lse 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、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 vo
13、ltage levels in the signal. This stream can then be applied, frequency modulation. sampling ：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 amplitud
14、e of the nth pulse equals the amplitude of V(t) at t= nT. consists of ：由.组成 pulse train ：脉冲串 amplitude：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 twic
15、e as large as the highest frequency component in the spectrum of V(t), the amplitudes of the pulses 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
16、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 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 (telephone) 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。,
