四川邮电职业技术学院教案专用纸 Teaching plan English for Lecturer Wangwei-Zhuang Course Unit One Telecommunications Number Teaching Grade Lecturing Mod Content The Principle of PCM Class Hours2 Periods 1. to know the three basic of PCM: Sampling Quantizin Teaching 2. to understand that PCM is the heart of technology in communications in Objectives today's digita/ world. 3. to master the technical terms: PCM sampling quantizing encoding pulse stream Focal 1. Focal Points:. The three processes of PCM Difficult 2. Difficult Points: the conversion of the analogue signals into binary form; The technical P oInts terms in the text eaching Methods Ways of lecturing, multimedia demonstration and speech interacting are applied to achieve the most understanding of the text intended Applied Discussion: What is the heart of technology in commun ications in today's digital world? (Topic) Exercises Exercises:共2道题 and Assignments 1. to collect the materials related to PCM 2. to apply the principle of PCM to the practice 1. Zhang Daozhen, ed Practical English Grammar (the 3rd Revision). Shanghai: the Commercial press. 1992 2. Shanghai Translation Publishing House, edu. New English-Chinese Bibliography Dictionary. Shanghai: Shanghai Translation Publishing House, 1988 3. Posts and Telecom Press, edu. English-Chinese Telecommunications Technology Dictionary. Bei jing: Posts and Telecom Press, 1997 4. Zhang Xiaohua and Shi Fangwen, ed English for Telecommunications(the 4 Page 1 of Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 1 of 12 Teaching Plan of English for Telecommunications Unit One Teaching Plan Lecturer Wangwei-zhuang Course English for Telecommunications Lesson Number Unit One Time Grade Teaching Mode Lecturing Content The Principle of PCM Class Hours 2 Periods Teaching Objectives 1． to know the three basic processes of PCM: Sampling Quantizing Encoding 2． to understand that PCM is the heart of technology in communications in today’s digital world. 3． to master the technical terms: PCM sampling quantizing encoding pulse stream… Focal & Difficult Points 1． Focal Points：. The three processes of PCM 2． Difficult Points：the conversion of the analogue signals into binary form; The technical terms in the text. Teaching Methods Applied Ways of lecturing, multimedia demonstration and speech interacting are applied to achieve the most understanding of the text intended. Discussion, Exercises and Assignments Discussion：What is the heart of technology in communications in today’s digital world？（Topic） Exercises：共 2 道题 Assignments： 1. to collect the materials related to PCM. 2. to apply the principle of PCM to the practice Bibliography 1. Zhang Daozhen,ed.Practical English Grammar (the 3rd Revision).Shanghai: the Commercial Press,1992 2. Shanghai Translation Publishing House, edu. New English-Chinese Dictionary. Shanghai: Shanghai Translation Publishing House,1988. 3. Posts and Telecom Press, edu. English-Chinese Telecommunications Technology Dictionary. Beijing: Posts and Telecom Press,1997 4. Zhang Xiaohua and Shi Fangwen,ed.English for Telecommunications (the 4th
四川邮电职业技术学院教案专用纸 Version). Beijing: Beijing of posts and telecommunicat Press. 2004 5. Xu Xiulan. English for Computers and Telecommunications (the 3re Revision). Beijing: Beijing University of Posts and Telecommunications Press. 2004 Teaching Plan of English for Telecommuni Unit One
四川邮电职业技术学院教案专用纸 Page 2 of 12 Teaching Plan of English for Telecommunications Unit One Version).Beijing: Beijing University of Posts and Telecommunications Press,2004 5. Xu Xiulan.English for Computers and Telecommunications (the 3rd Revision) .Beijing: Beijing University of Posts and Telecommunications Press,2004
四川邮电职业技术学院教案专用纸 Teaching Content Contents Time Apparatuses I. Brief-Introduction to English on Telecommunications 3 From this period on, we are g to learn English on Telecommunications, which is one of the English for special projector, purposes. Learning this course, we will enlarge our vocabulary in the field of telecommunications and information; get familiar with 2 mins loud the terms in it: get to know the characteristics of writing style of telecommunications English and master the translation skills of it: thus greatly improve our professional qualities and communicative competency in this globalized world in the anguage teaching II. Pre-reading Activities system, Introduction to Pulse Code Modulation(PCM) blackboard Ask the ss the following two questions related to the theme of the text recorder What is the heart of technology in communications in today's digital world? DVD, Possible answers: PCM, which is short for pulse code modulation (to be discussed in depth later) is the heart of technology in mmunications in today's digital world. It is a process in which analog signals are converted to digital form the analog signal is represented by a series of pulses and non -pulses(1 or o respectively ). At this stage to fully understand we can refer back to the notes on signals Why Pcm? Possible answers: The stream of pulses and non-pulse streams of 1s and 0s are not easily affected by interference and noise. Even in the presence of noise, the presence or absence of a pulse can be easily determined. Since PCm is digital, a more general reason would be that digital signals are easy to process by cheap standard techniques. This makes it easier to implement complicated communication systems such as telephone networks (covered later in this course) The practica l implementation of PCM makes use of other processes. The processes are carried out in the order in which they appear below Filtering Sampling Page 3 of 12 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 3 of 12 Teaching Plan of English for Telecommunications Unit One Teaching Content Contents Time Teaching Apparatuses I. Brief-Introduction to English on Telecommunications From this period on, we are going to learn English on Telecommunications, which is one of the English for special purposes. Learning this course, we will enlarge our vocabulary in the field of telecommunications and information; get familiar with the terms in it; get to know the characteristics of writing style of telecommunications English and master the translation skills of it; thus greatly improve our professional qualities and communicative competency in this globalized world in the information age. II. Pre-reading Activities Introduction to Pulse Code Modulation (PCM) Ask the Ss the following two questions related to the theme of the text: What is the heart of technology in communications in today’s digital world？ Possible answers: PCM, which is short for Pulse code modulation (to be discussed in depth later) is the heart of technology in communications in today’s digital world. It is a process in which analog signals are converted to digital form. The analog signal is represented by a series of pulses and non-pulses (1 or 0 respectively). At this stage to fully understand we can refer back to the notes on signals. Why PCM? Possible answers: The stream of pulses and non-pulse streams of 1’s and 0’s are not easily affected by interference and noise. Even in the presence of noise, the presence or absence of a pulse can be easily determined. Since PCM is digital, a more general reason would be that digital signals are easy to process by cheap standard techniques. This makes it easier to implement complicated communication systems such as telephone networks (covered later in this course). The practical implementation of PCM makes use of other processes. The processes are carried out in the order in which they appear below: • Filtering • Sampling 3 mins 2 mins 60 mins computer， projector， loud speaker， audio-visual language teaching system， blackboard， recorder， DVD， radio， hanging chart， model
四川邮电职业技术学院教案专用纸 Quantizing Encoding III While-reading Activities i. New Words And phrases principle[' pr i nsi pl]n,原理 be de pendent on做赣,取决于 sample[ s aem p1]vt采样样值 quantize[ k won aiz]v量化分层 mIns code[koud]v编码n码 scheme[ski:m]n.方案设排啡 describe[dis" krai b]vt述描述 description皺錋述描述 ampHtude[ aem p Ii tj u:d]n幅,幅度 binary ['ba i nar i]a二进的 mIns minimum[ m I n I mam]n.最小值最小量 theoretical[ eiare ti kal]a理论上的 I mins repetition[repi' t ifan]n.复夏 reexamination再考 maximun[ maeksimam]n.最大值 reduce[ri:'dju:s]v.少缩小 terchange[ i n tate i nd]v.互换轶换 method ['m eead]n.菇發 overcome[ o va kam]v.克服打败征服报 environment[in' v a bremen t]n.环境周围觏 Lightning ['l a i t n il6]n.电光闪电雷电 strike[ straik]n.击戴打 spark[spck]ⅵ发花批 ignition[ig" n i n]n.献火犍置 signaltonoise ratio僧颚 satellte ' sati la i tnpE terrestrial[ti' rest rie1]a地的地面的大地 by comparison比来下 parameter[ pa' raem i ta]n.参澈数 attenuation浏减表耗 inherent[in' h ie ran t]a.固有的 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 4 of 12 Teaching Plan of English for Telecommunications Unit One • Quantizing • Encoding III. While-reading Activities i. New Words And Phrases p ri nc i p le ［ ' ｐ ｒ ｉ ｎ ｓ ｉ ｐ ｌ ］ n . 原 理 b e de pe n d e n t o n 依 赖 ， 取 决 于 sample ［'ｓæｍｐｌ］vt.采样；样值 quantize ［'ｋｗɔｎｔａｉｚ］v.量化，分层 code ［ｋｏｕｄ］v.编码；n.码 scheme ［ｓｋｉ: ｍ］n.方案，设计，安排 describe ［ｄｉｓ'ｋｒａｉｂ］vt.叙述，描述 description 叙述，描述 amplitude ［'æｍｐｌｉｔｊｕ:ｄ］n.幅，幅度 binary ［'ｂａｉｎəｒｉ］a.二进制的 minimum ［'ｍｉｎｉｍəｍ］n. 最小值，最小量 theoretical ［θｉə'ｒｅｔｉｋəｌ］a. 理论上的i repetition ［ｒｅｐｉ'ｔｉʃəｎ］n. 重复，反复 reexamination 再审查，重考 maximum［'mæksiməｍ］n. 最大值 reduce ［ｒｉ:'ｄｊｕ:ｓ］v. 减少，缩小 interchange［ｉｎｔə'ʧｅｉｎʤ］v. 互换，转换 method［'ｍｅθəｄ］n. 方式，方法，手段 overcome ［ｏｕｖə'ｋʌｍ］v. 克服,打败,征服 environment［ｉｎ'ｖａｉəｒəｍəｎｔ］n. 环境,周围情况 lightning ［'ｌａｉｔｎｉɧ］n. 电光，闪电，雷电 strike ［ｓｔｒａｉｋ］n. 击，敲，打 spark ［ｓｐα:ｋ］vi. 发火花，打火，闪光 ignition ［ｉｇ'ｎｉʃəｎ］n. 点火，点火装置 signaltonoise ratio 信号噪声比 satellite ［'ｓæｔｉｌａｉｔ］n.卫星 terrestrial［ｔｉ'ｒｅｓｔｒｉəｌ］a.地球的,地面的,大地的 by comparison 比较起来，相对之下 parameter［ｐə'ｒæｍｉｔə］n. 参数，系数 attenuationn. 衰减，衰耗 inherent［ｉｎ'ｈｉəｒəｎｔ］a. 固有的，内在的 2mins 4 mins 1 mins
四川邮电职业技术学院教案专用纸 assume[ssju:m]v假髋定 decoder解器 codec编译码器 interleave[int"li:]t.彌插殲播接 appropriate[s' proup r i t]a.适当的合适的 ik]a唯的猫 reoccur再先生再姓生 ii. Passage-reading Activities The Principle of PCM(1) PcM原理 PCM is dependent on(22_three separate operations, sampling, quantizing, and coding(2 ). Many different schemes for performing 2)these three functions have evolved during recent years, and we shall describe the main ones PCM的构成依赖于三个环节即采样、量化和编码.近年来人们对这 三个环节的实现提出了许多不同的方案我们将对其中一些主要的方案进 行讨论 (2). be dependent on依靠,依赖,取决于 (2). performing是 perform的动名词动名词虽为名词,但仍 保留着动词的某些特征,例如它仍可带有动词宾语本句中的 these three functions就是 performing的宾语 本课中这类例子很多,例如第四段中的最后一句中 Consequently there is an inherent advantage for overcoming noisy environments by choosing digital transmission. 句中的 overcomIng和 choosing都是动名词且带有自己的动词宾语. 另有理论认为PCM分为四过程,如下: The practical implementation of PCM makes use of other processes. The processes are carried out in the order in which they appear below Fil tering Quantizing The filtering stage removes frequencies above the highest signal frequency. These frequencies if not removed, may cause problems when the signal is going through the stage of sampling. Sampling of a waveform means determining instantaneous ampli tudes of a signal at fixed intervals. You may have a problem in understanding what this sentence means, but if you take time to look at Figure 7 on the following Slide you should be able to understand. Page 5 of 12 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 5 of 12 Teaching Plan of English for Telecommunications Unit One assume ［ə'ｓｊｕ:ｍ］v. 假设，假定 decoder 解(译)码器 codec 编译码器 interleave ［ｉｎｔ'ｌｉ:ｖ］vt. 交插，交错，插接 appropriate ［ə'ｐｒｏｕｐｒｉｔ］a. 适当的，合适的 unique ［ｊｕ:'ｎｉｋ］a. 唯一的，独特的 reoccur 再发生，再次发生 ii. Passage-reading Activities The Principle of PCM(1) PCM 原理 PCM is dependent on (2 ) three separate operations, sampling, quantizing, and coding (2’). Many different schemes for performing (2) these three functions have evolved during recent years, and we shall describe the main ones. PCM 的构成依赖于三个环节,即采样、量化和编码. 近年来,人们对这 三个环节的实现提出了许多不同的方案,我们将对其中一些主要的方案进 行讨论. ◼ （2）. be dependent on 依靠，依赖，取决于. ◼ （2’）. performing 是 perform 的动名词.动名词虽为名词，但 仍 保留着动词的某些特征，例如它仍可带有动词宾语.本句中的 these three functions 就是 performing 的宾语. 本课中这类例子很多，例如第四段中的最后一句中： Consequently there is an inherent advantage for overcoming noisy environments by choosing digital transmission. 句中的 overcoming 和 choosing 都是动名词且带有自己的动词宾语. ◼ 另有理论认为ＰＣＭ分为四过程，如下： ◼ The practical implementation of PCM makes use of other processes. The processes are carried out in the order in which they appear below: Filtering Sampling Quantizing Encoding The filtering stage removes frequencies above the highest signal frequency. These frequencies if not removed, may cause problems when the signal is going through the stage of sampling. Sampling of a waveform means determining instantaneous amplitudes of a signal at fixed intervals. You may have a problem in understanding what this sentence means, but if you take time to look at Figure 7 on the following Slide, you should be able to understand
四川邮电职业技术学院教案专用纸 In these descriptions we shall see how a speech channel of elephone quality may be conveyed as a series of amplitude values, each value being represented ( 3), that is, coded, as(3,)a sequence of 8 binary digits 在这些讨论中,我们会看到话路中的语声信号是如何转换成一个幅值 序列的,而每个幅值又被编码,即以8位二进制数的序列表示 (3). each value being represented这是一种独立分词结构,用 来表示一种伴随状态,作状语可译成:“而每一幅值被表示为”.独立分 词结构在科技文章中相当常见,例如 There are many kinds of steel, each having its uses in industry. 译为:“钢有许多种,在工业中每种都有它自己的用途” 独立分词结构还可以表示时间、原因或条件等,对主句进行补充说明 例如表示原因 r The resistance being very high, the current in the circuit was 译为:“由于电阻很高,故电路里的电流很小 (3,). as a sequence of8 binary digits句中的as意为“作为, 表为,成为”.该短语可译成:“(表为)8位二进制码的序列” Furthermore(4), we shall prove that a minimum theoretical sampling frequency of order 6.8 kilohertz(kHz) is required to convey a voice channel occupying the range 300 Hz to 3. 4kHz(4a). Practical equipments, however, normally use a sampling rate of 8 kHz, and 8-digits per sample value are used, the voice channel becomes represented by a stream of pulses(4b)with a repetition rate of 64 kHz. Fig. 1-l illustrates the sampling, quantizing, and coding processes. 而且,我们将证明,为了变换频率范围300Hz34KHz的话路信号,理论 上的最小采样频率为608KHz但是,实际设备通常用8Kz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为64KHz的脉冲流来 表示的.图1-1表示了采样、量化和编码的过程 (4). furthermore:adv.“而且;此外” Furthermore, these child-raising families may raise other eople 's children in addition to their own而且,这些抚养孩子 的家庭除了自己的孩子外也可以抚养其他人家的孩子 The house is too small. and furtherm office.这座房子太小,而且离办公地点也太远。 同义词: again,also, besides, by the same token, in addition, likewise, similarly, then, too (4a)。脉冲流 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 6 of 12 Teaching Plan of English for Telecommunications Unit One In these descriptions we shall see how a speech channel of telephone quality may be conveyed as a series of amplitude values, each value being represented (3), that is, coded, as (3’) a sequence of 8 binary digits. 在这些讨论中,我们会看到话路中的语声信号是如何转换成一个幅值 序列的,而每个幅值又被编码,即以 8 位二进制数的序列表示. （3）. each value being represented 这是一种独立分词结 构，用 来表示一种伴随状态，作状语.可译成：“而每一幅值被表示为”.独立分 词结构在科技文章中相当常见，例如： There are many kinds of steel, each having its uses in industry. 译为：“钢有许多种，在工业中每种都有它自己的用途”. 独立分词结构还可以表示时间、原因或条件等，对主句进行补充说明. 例如表示原因： The resistance being very high, the current in the circuit was low. 译为:“由于电阻很高，故电路里的电流很小”. (3’).as a sequence of 8 binary digits 句中的 as 意为“作为， 表为，成为”.该短语可译成:“(表为)8 位二进制码的序列”. Furthermore (4), we shall prove that a minimum theoretical sampling frequency of order 6.8 kilohertz (kHz) is required to convey a voice channel occupying the range 300 Hz to 3.4 kHz(4a). 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 (4b) with a repetition rate of 64 kHz. Fig. 1-1 illustrates the sampling, quantizing, and coding processes. 而且,我们将证明,为了变换频率范围 300Hz~3.4KHz 的话路信号,理论 上的最小采样频率为608KHz.但是,实际设备通常用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为 64KHz 的脉冲流来 表示的. 图 1-1 表示了采样、量化和编码的过程. （4）. furthermore: adv.“而且；此外” Furthermore, these child-raising families may raise other people‘s children in addition to their own. 而且,这些抚养孩子 的家庭除了自己的孩子外也可以抚养其他人家的孩子。 The house is too small, and furthermore, it's too far from the office. 这座房子太小,而且离办公地点也太远。 同义词：again, also, besides, by the same token, in addition, likewise, similarly, then, too. (4a)。 脉冲流
四川邮电职业技术学院教案专用纸 (4b). occupying是 occupy的现在分词 动词的-ng形式可以作为名词用,称为动名词,本课注释(2)已对此 作了介绍。动词的-ing形式亦可作形容词用(称现在分词).它一般修饰该 动作的发出者,而且它亦可带有自己的宾语,例如本句中的:“ a volce channe1 occupying the range300zto3.4kHz”,该短语可译为:“占 有300Hz到3.4kHz频率范围的话路 Reexamination of our simple example shows us that the speech signal of maximum(5) frequency 3. 4 kHz has been represented by a signal of frequency 64 kHz. 让我们再研究一下上面提到的简单例子可以看出,最高频率为 3.4KHz的话音信号是用64KHZ的(脉冲流)信号来表示的 (5).n.(p1. maximums,mma[mB])最大量;最大数;最高点极点 最高额,最大限度【数】极大(值);最大(值)(发展的)顶峰时期 reach a maximum达到顶点 The excitement was at its maximum.兴奋到极点。 The sound has reached its maximum.声音达到最高音位。 反义词:mi However, if only 4-digits per sample value had been used, the quality of transmission would drop, the repetition rate of the pulses would be reduced to 32 kHz. Thus the quality of transmission is dependent on the pulse repetition rate, and for digital ommunication systems these two variables may be interchanged most efficiently. 但是,如果每个样值只用4位码表示,则传输质量会下降,而脉冲的重 复速率也将减小到32Kz.因而传输质量是取决于脉冲重复速率的对于数 字通信系统,这两个量之间极明显地相互影响着 Digital transmission provides a powerful method for overcoming noisy environments. Noise can be introduced into transmission path in many different ways; perhaps via a nearby lightning strike, the sparking of a car ignition system, or the thermal low-level noise (6)within the communication equipment itsel 数字传输对于克服噪声环境的影响提供了一个强有力的手段噪声可 以以多种不同的方式进入传输信道,比如说因为附近的闪电、汽车点火系 统的打火或因通信设备本身低电平所致 (6).本句中的几个词组可译为: 1 ightning strike打雷 sparking of a car ignition system汽车点火系统的打火 therma11ow-1eve1 noise低电平的热噪声 It is the relationship of the true signal to the noise signal known as the signal-to-noise ratio(7)which is of the most interest Page 7 of 12 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 7 of 12 Teaching Plan of English for Telecommunications Unit One (4b). occupying 是 occupy 的现在分词. 动词的-ing 形式可以作为名词用，称为动名词，本课注释(2)已对此 作了介绍。动词的-ing 形式亦可作形容词用(称现在分词).它一般修饰该 动作的发出者，而且它亦可带有自己的宾语，例如本句中的:“a voice channel occupying the range 300Hz to 3.4kHz”. 该短语可译为:“占 有 300Hz 到 3.4kHz 频率范围的话路”. Reexamination of our simple example shows us that the speech signal of maximum (5) frequency 3.4 kHz has been represented by a signal of frequency64 kHz. 让我们再研究一下上面提到的简单例子.可以看出 ,最高频率为 3.4KHz 的话音信号是用 64KHZ 的(脉冲流)信号来表示的. （5）. n.(pl. maximums, -ma[-mE])最大量; 最大数; 最高点极点; 最高额, 最大限度【数】极大(值); 最大(值)(发展的)顶峰时期 reach a maximum 达到顶点 The excitement was at its maximum. 兴奋到极点。 The sound has reached its maximum. 声音达到最高音位。 反义词：minimum However, if only 4-digits per sample value had been used, the quality of transmission would drop, and the repetition rate of the pulses would be reduced to 32 kHz. Thus the quality of transmission is dependent on the pulse repetition rate, and for digital communication systems these two variables may be interchanged most efficiently. 但是,如果每个样值只用 4 位码表示,则传输质量会下降,而脉冲的重 复速率也将减小到 32KHz.因而传输质量是取决于脉冲重复速率的.对于数 字通信系统,这两个量之间极明显地相互影响着. Digital transmission provides a powerful method for overcoming noisy environments. Noise can be introduced into transmission path in many different ways; perhaps via a nearby lightning strike, the sparking of a car ignition system, or the thermal low-level noise (6) within the communication equipment itself. 数字传输对于克服噪声环境的影响提供了一个强有力的手段.噪声可 以以多种不同的方式进入传输信道,比如说因为附近的闪电、汽车点火系 统的打火或因通信设备本身低电平所致. （6）.本句中的几个词组可译为: lightning strike 打雷 sparking of a car ignition system 汽车点火系统的打火 thermal low-level noise 低电平的热噪声 It is the relationship of the true signal to the noise signal, known as the signal-to-noise ratio (7) which is of the most interest
四川邮电职业技术学院教案专用纸 to(7')the communication engineer. Basically, if the signal is very large compared to the noise leveL, (7a)then a perfect message can take place; however, this is not always the case(7b) 正是这种被称为信噪比的即真实信号与噪声的关系引起了通信工程 师的极大的兴趣.从本质上讲如果信号比噪声电平大得多则信息的传输 是完美的但是,实际情况并不总是这样 (7), known as the signal-to- noise ratio译为“称为信号噪声 比 (7’),Beof+n.结构 Be of importance=be important be of the most interest to= be most interesting to 7a). compared to the noise level意为:“与噪声电平相比” (7b). this is not always the case:实际情况并非如此 For example, the signal received from a satellite, located ii far outer space( 8), is very weak and is at a level only slightly above that of the noise. ALternative examples(8,)may be found within terrestrial systems where, although the message signal i strong, so is the noise power. 例如,从位于遥远太空中的卫星接收的信号极其微弱其电平仅比噪 声稍高一点.地面系统则是另一类例子足管信号很强声也很强 (8). Located in far outer space这是一种分词短语结构 located 是动词的d形式称为过去分词,起形容词的作用,在句中作定语这种 分词往往用来修饰原来动词动作的承受者例如: The trees planted by me have growm up.“我种的树已长大了.” 再例如 Electromotive force results in electrical pressure, compared to water pressure.“电动势产生电压,电压好比水压” 所以课文中的这一短语可译为:“位于远太坐中的(卫星 (81). Alternative ad.随便一个的,二者择的(三者或以 上的选择用 choice) The way was blocked, so we went by an alternative road. t 被挡住了,因此我们走了另一条路。 n.择;选择余地 I wanted to go out, but I had no alternative but to staying at home.我想出去,可是没钱,只能待在家里 have no alternative but to go on.除了继下去我们没有选 择的余地。 There was no other alternative but to fight tili the victory. 除了战↓直到胜利别无选择。 Page 8 of 12 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 8 of 12 Teaching Plan of English for Telecommunications Unit One to (7’) the communication engineer. Basically, if the signal is very large compared to the noise level,(7a) then a perfect message can take place; however, this is not always the case (7b). 正是这种被称为信噪比的即真实信号与噪声的关系引起了通信工程 师的极大的兴趣.从本质上讲,如果信号比噪声电平大得多,则信息的传输 是完美的.但是,实际情况并不总是这样. （7）. known as the signal-to-noise ratio 译为“称为信号噪声 比”. （7’）. Be of + n. 结构 Be of importance=be important be of the most interest to= be most interesting to （7a）. compared to the noise level 意为:“与噪声电平相比”. （7b）. this is not always the case: 实际情况并非如此． For example, the signal received from a satellite, located in far outer space (8), is very weak and is at a level only slightly above that of the noise. Alternative examples (8’) may be found within terrestrial systems where, although the message signal is strong, so is the noise power. 例如, 从位于遥远太空中的卫星接收的信号极其微弱,其电平仅比噪 声稍高一点.地面系统则是另一类例子,尽管信号很强,噪声也很强. （8）. located in far outer space 这是一种分词短语结构.located 是动词的-ed 形式，称为过去分词，起形容词的作用，在句中作定语.这种 分词往往用来修饰原来动词动作的承受者.例如: The trees planted by me have grown up.“我种的树已长大了.” 再例如: Electromotive force results in electrical pressure, compared to water pressure.“电动势产生电压，电压好比水压” 所以课文中的这一短语可译为:“位于遥远太空中的(卫星)”. （8’）. Alternative adj.随便一个的；二者择一的 (三者或以 上的选择用 choice) The way was blocked, so we went by an alternative road.这条 路被挡住了，因此我们走了另一条路。 n. 抉择；选择余地 I wanted to go out, but I had no money. I had no alternative but to staying at home.我想出去，可是没钱；只能待在家里。 We have no alternative but to go on.除了继续下去,我们没有选 择的余地。 There was no other alternative but to fight till the victory. 除了战斗直到胜利,别无选择
四川邮电职业技术学院教案专用纸 If we consider binary transmission, the complete information about a particular message will always be obtained by simply detecting the presence or abs sence o 研究二进制信号的传输可见,只要简单地去判别脉冲的”有”和” 无”,我们就获得了一条消息的全部信息 By comparison, most other forms of transmission systems convey the message information using the shape, or level of the transmitted signal(9): parameters that are most easily affected by the noise and attenuation introduced by the transmission path 相比之下许多其他形式的传输系统是利用被传信号的波形或电平来 传送信息的,而这些参数又极易受到传输途径中的噪声和衰耗的影响 (9). By comparison相比之下 (9 '). using the shape, or level of transmitted signal >y 现在分词短语结构,作伴随情况状语,可译为:“用传输信号的波形或电 平(来传送信息 类似的例子还有 The rockets rose hissing over the launching site.“火箭在发 射场的上空嘶嘶地上升.” 再例如 They sat together carefully studing the design of th circuits “他们坐在一起仔细地研究着那些电路的设计 对课文中的这个句子,全句可译为:“相比之上,许多其他形式的传 输系统是利用被传信号的波形或电平来传送信息的,而这些参数又极易受 到传输途径中的噪声和衰耗的影响.” 1y (10) the dvantage(10’)fo overcoming noisy environments by choosing digital transmission. 因此选择数字传输系统在克服噪声环境方面有其固有的优势 (10), consequently:adv.,conj所以,因此 Mr. Foster has never been to China. Consequently /Hence he knows very little about it. 福斯特先生从未去过中国所以对中国了解得很少。“ 同义词: accordingly, hence,& s a result, therefore (101). inherent advantage固有的优势 So far in this discussion we have assumed that each voice channel has a separate coder, the unit that converts sample amplitude values to a set of pulses, and decoder the unit that performs the reverse operation( 11).This need not be so and systems are in operation where a single codec (i.e, coder and its associated decoder)is shared between 24, 30, or even 120 separate channels Page 9 of 12 Teaching Plan of English for Telecommunications Unit One
四川邮电职业技术学院教案专用纸 Page 9 of 12 Teaching Plan of English for Telecommunications Unit One If we consider binary transmission, the complete information about a particular message will always be obtained by simply detecting the presence or absence of the pulse. 研究二进制信号的传输可见,只要简单地去判别脉冲的”有”和” 无”,我们就获得了一条消息的全部信息. By comparison, most other forms of transmission systems convey the message information using the shape, or level of the transmitted signal (9); parameters that are most easily affected by the noise and attenuation introduced by the transmission path. 相比之下,许多其他形式的传输系统是利用被传信号的波形或电平来 传送信息的,而这些参数又极易受到传输途径中的噪声和衰耗的影响. （9）. By comparison 相比之下 （9’）. using the shape, or level of transmitted signal 为 现在分词短语结构，作伴随情况状语，可译为:“用传输信号的波形或电 平(来传送信息)”. 类似的例子还有: The rockets rose hissing over the launching site.“火箭在发 射场的上空嘶嘶地上升.” 再例如: They sat together, carefully studing the design of the circuits. “他们坐在一起仔细地研究着那些电路的设计.” 对课文中的这个句子，全句可译为:“相比之上，许多其他形式的传 输系统是利用被传信号的波形或电平来传送信息的，而这些参数又极易受 到传输途径中的噪声和衰耗的影响.” Consequently (10) there is an inherent advantage (10’) for overcoming noisy environments by choosing digital transmission. 因此选择数字传输系统在克服噪声环境方面有其固有的优势. （10）.consequently: adv., conj.所以，因此 Mr. Foster has never been to China. Consequently / Hence he knows very little about it. “福斯特先生从未去过中国,所以对中国了解得很少。“ 同义词：accordingly, hence, as a result, therefore. （10’）. inherent advantage 固有的优势． So far in this discussion we have assumed that each voice channel has a separate coder, the unit that converts sampled amplitude values to a set of pulses; and decoder, the unit that performs the reverse operation (11). This need not be so and systems are in operation where a single codec (i.e., coder and its associated decoder) is shared between 24, 30, or even 120 separate channels
四川邮电职业技术学院教案专用纸 到目前为止在这个讨论中,我们一直假定每个话路各有一个编码器 和解码器前者是将幅度采样值变成脉冲而后者施行相反的变换这种设 置并非必需.在实际运行的PcM系统中,单一的编、译码器为24路、30路, 甚至120路所共用(注:在当代PQM设备中编、译码器系分路设备,即每 个话路各有一套.) (11). So far in this discussion we have assumed that each voice channel has a separate coder, the unit that converts sampled amplitude values to a set of pulses; and decoder the unit that performs the reverse operation.本句理解和翻译应注意结构的分 析.在宾语从句 that each voice channel has…中has带了两个并列 的宾语 coder, decoder;且这两个成分又分别带了非限制性定语从句 A high-speed electronic switch(12a) is used to present the analog information signal of each channel, taken in turn(12b),to The codec is then arranged to sequentially sample the value, and code(12c) this value into the 8-digit sequence. 一个高速的电子开关被用来将每一话路的模拟信号依次地送往编、译 码器.然后编、译码器再顺序采样幅值并把这个幅值编成8位码序列 (12a). A high- speed electronic switch:一个高速电子开关 (14b). taken in turn轮流地,依次地 (12c), Code此处作动词,编码 Thus the output to the codec may be seen as a sequence of 8 pul relating to channel 1, then channel 2, and so on. This unit is called a time division multiplexer (TDM), and is illustrated in Fig. 1-2 (13). The multiplexing principle that is used is known as word interleaving. Since the words, or 8-digit sequences, are interleaved in time 因此从编译码器输出的信息就是一个分别对应于话路1,话路2,等 等的8位码序列.这种设备称为时分复用,如图1-2所示.音域8位码的 码字序列按时间顺序插接在一起,所以上面的复用原则称为码字插接 At the receive terminal a de-multiplexer is arranged to separate the 8-digit sequences into the appropriate(14)channels. The reader may ask, how does the de-multiplexer know which group of 8-digits relates to channel 1, 2, and so on? Clearly this important 接收端设置了分路设备将8位码序列分配到相应的话路中读者也许 会问,分路设备怎么知道哪一个8位码组对应于第1路、第2路极其他各 路呢?显然这是很重要的 (14). appropriate:adj适合的;适当的;相称的 appropria example适当的例子 appropriate manners适当的态度 Write in a style appropriate to your subject.用与你的题目相 Page 10 of 12 Teaching Plan of English for Telecommunications Unit On
四川邮电职业技术学院教案专用纸 Page 10 of 12 Teaching Plan of English for Telecommunications Unit One 到目前为止,在这个讨论中, 我们一直假定每个话路各有一个编码器 和解码器.前者是将幅度采样值变成脉冲,而后者施行相反的变换,这种设 置并非必需.在实际运行的 PCM 系统中,单一的编、译码器为 24 路、30 路, 甚至 120 路所共用(注: 在当代 PCM 设备中,编、译码器系分路设备,即每 个话路各有一套.) （11）. So far in this discussion we have assumed that each voice channel has a separate coder, the unit that converts sampled amplitude values to a set of pulses; and decoder, the unit that performs the reverse operation. 本句理解和翻译应注意结构的分 析． 在宾语从句 that each voice channel has…中 has 带了两个并列 的宾语 coder, decoder；且这两个成分又分别带了非限制性定语从句． A high-speed electronic switch (12a) is used to present the analog information signal of each channel, taken in turn (12b), to the codec. The codec is then arranged to sequentially sample the amplitude value, and code (12c) this value into the 8-digit sequence. 一个高速的电子开关被用来将每一话路的模拟信号依次地送往编、译 码器.然后编、译码器再顺序采样幅值并把这个幅值编成 8 位码序列. （12a）. A high-speed electronic switch : 一个高速电子开关 （14b）. taken in turn 轮流地，依次地 （12c）. Code 此处作动词，编码． Thus the output to the codec may be seen as a sequence of 8 pulses relating to channel 1, then channel 2, and so on. This unit is called a time division multiplexer (TDM), and is illustrated in Fig. 1-2 (13). The multiplexing principle that is used is known as word interleaving．Since the words, or 8-digit sequences, are interleaved in time. 因此从编译码器输出的信息就是一个分别对应于话路 1, 话路 2, 等 等的 8 位码序列. 这种设备称为时分复用,如图 1-2 所示. 音域 8 位码的 码字序列按时间顺序插接在一起,所以上面的复用原则称为码字插接. At the receive terminal a de-multiplexer is arranged to separate the 8-digit sequences into the appropriate (14) channels. The reader may ask, how does the de-multiplexer know which group of 8-digits relates to channel 1, 2, and so on? Clearly this is important! 接收端设置了分路设备,将 8 位码序列分配到相应的话路中.读者也许 会问,分路设备怎么知道哪一个 8 位码组对应于第 1 路、第 2 路极其他各 路呢?显然这是很重要的. （14）. appropriate: adj.适合的; 适当的; 相称的 appropriate example 适当的例子 appropriate manners 适当的态度 Write in a style appropriate to your subject.用与你的题目相
