1、Unit 4 Electronic systems,Lesson 11 The mobile telephone System (II)电子信息工程专业英语教程任治刚 主编 电子工业出版社 ,2018/12/6,电子信息工程专业英语教程,2,Lesson 11 The mobile telephone System (II),Backgrounds Text tour Language in use Vocabulary Structure Reading/writing techniques,2018/12/6,电子信息工程专业英语教程,3,Terminology TDM 时分复用 FDM
2、频分复用 PCM 脉冲编码调制 PCS 个人通信系统 spread spectrum communication扩频通信,Backgrounds,2018/12/6,电子信息工程专业英语教程,4,Text tour,Outline D-AMPS -The Digital Advanced Mobile Phone System GSM - The Global System for Mobile Communications CDMA - Code Division Multiple Access,2018/12/6,电子信息工程专业英语教程,5,D-AMPS is the second ge
3、neration of AMPS Fully digital International Standard: IS-54 and IS-136 D-AMPS and AMPS share 30 kHz channel upstream channels in the 18501910 MHz range downstream channels in the 19301990 MHz range D-AMPS differs in ,D-AMPS The Digital Advanced Mobile Phone System,2018/12/6,电子信息工程专业英语教程,6,Figure 4.
4、2. (a) A D-AMPS channel with 3 users. (b) A D-AMPS channel with 6 users.,D-AMPS The Digital Advanced Mobile Phone System,2018/12/6,电子信息工程专业英语教程,7,GSM is similar to D-AMPS in cellular system FDM is used transmitting on one frequency and receiving on a higher frequency a single frequency pair is split
5、 by TDM into time slots shared by multiple mobiles.,GSM The Global System for Mobile Communications,2018/12/6,电子信息工程专业英语教程,8,GSM is different from D-AMPS in the GSM channels are much wider (200 kHz vs. 30 kHz) hold relatively few additional users (3 vs. 8) GSM has a much higher data rate per user,GS
6、M The Global System for Mobile Communications,2018/12/6,电子信息工程专业英语教程,9,Figure 4.3. GSM uses 124 frequency channels, each of which uses an eight-slot TDM system.,GSM The Global System for Mobile Communications,2018/12/6,电子信息工程专业英语教程,10,Figure4.4. A portion of the GSM framing structure.,GSM The Global
7、 System for Mobile Communications,2018/12/6,电子信息工程专业英语教程,11,Completely different from D-AMPS and GSM An analogy FDMA is TDMA is CDMA is An example Practical considerations for CDMA,CDMA Code Division Multiple Access,2018/12/6,电子信息工程专业英语教程,12,Vocabulary modulation, approximation, conflict, comparable
8、, random, complement, inverse, spectrum, parallel, scheme, complicate Structure Reading/writing techniques,Language in use,2018/12/6,电子信息工程专业英语教程,13,Vocabulary,2018/12/6,电子信息工程专业英语教程,14,Modulation in dictionary,A change in stress, pitch, loudness, or tone of the voice; an inflection of the voice. Th
9、e variation of a property of an electromagnetic wave or signal, such as its amplitude, frequency, or phase. The process by which some characteristic of one wave is varied in accordance with another wave or signal. This technique is used in modems to make business machine signals compatible with comm
10、unication facilities. A method of representing data in magnetizable surface storage; for example, “modified frequency modulation”.,2018/12/6,电子信息工程专业英语教程,15,Modulation in text,On a D-AMPS mobile phone, the voice signal picked up by the microphone is digitized and compressed using a model that is mor
11、e sophisticated than the delta modulation and predictive encoding schemes. 在D-AMPS 移动电话上，语音信号由麦克风拾取之后，先进行数字化，然后使用比增量调制和预测编码更复杂的模型进行压缩。,2018/12/6,电子信息工程专业英语教程,16,Modulation in use,adaptive delta modulation 自适应增量调制 amplitude modulation 调幅 angle modulation 角调制(调频与调相) binary pulse-code modulation 二进制脉(冲
12、编)码调制 differential pulse code modulation 差值脉冲编码调制,2018/12/6,电子信息工程专业英语教程,17,Modulation in use,differential pulse code modulation 差分脉冲编码调制 direct frequency modulation 直接调频 displacement modulation (脉冲)相位位移调制 double-sideband modulation 双边带调制,2018/12/6,电子信息工程专业英语教程,18,Modulation in use,incidental phase
13、modulation 寄生调相 pulse-amplitude modulation 脉幅调制 quadrature modulation 正交调制, 直角相位调制 vestigial side band modulation 残留边带调制,2018/12/6,电子信息工程专业英语教程,19,Approximation in dictionary,The act, process, or result of approximating.接近 An inexact result adequate for a given purpose.近似值,2018/12/6,电子信息工程专业英语教程,20,
14、Approximation in text,To a first approximation, GSM is similar to D-AMPS. Both are cellular systems. 乍一看，GSM 和D-AMPS很相似。两者都是蜂窝系统。,2018/12/6,电子信息工程专业英语教程,21,Approximation in use,best polynomial approximation 最佳多项式逼近 closest rational approximation 最近分数, 最近有理近似法 difference approximation 差分近似 differenti
15、al approximation 微分逼近 digital approximation 数值逼近 engineering approximation 工程近似法 exponential approximation 指数近似,2018/12/6,电子信息工程专业英语教程,22,Approximation in use,finite-difference approximation 有限差分近似 least square approximation 最小二乘逼近 linear approximation 线性近似, 线性逼近 lumped parameter approximation 集中参数近
16、似 rational function approximation 有理函数逼近,2018/12/6,电子信息工程专业英语教程,23,Multiplex in dictionary,Relating to, having, or consisting of multiple elements or parts:复合的 Relating to or being a system of simultaneous communication of two or more messages on the same wire or radio channel.多路传输的 A building, espe
17、cially a movie theater or dwelling, with multiple separate units.复合式建筑 To send messages or signals simultaneously using a multiplex system.多路传输 To send simultaneously using a multiplex system.多路传输,2018/12/6,电子信息工程专业英语教程,24,Multiplex in text,With mobile telephony there is a huge gain from doing digit
18、ization and compression in the handset, so much so that in D-AMPS, three users can share a single frequency pair using time division multiplexing. 对于移动电话而言，在电话机内完成数字化并进行数据压缩有很大好处这样一来，3个D-AMPS用户可以通过时分复用共用一对频率。,2018/12/6,电子信息工程专业英语教程,25,Multiplex in use,code-division multiplex 码分多路通信 frequency multipl
19、ex 频率多工通信 frequency-division multiplex 频分多路复用 space division multiplex 空分多路通信 stereo multiplex 立体声多路传输,2018/12/6,电子信息工程专业英语教程,26,Multiplex in use,Simplex 单工通信 A term applied to a circuit or method of working in which data is transmitted in only one pre-assigned direction. Duplex 双工通信 ( full duplex,
20、half duplex) In data communication, pertaining to a simultaneous two-way independent transmission in both directions. Complex,2018/12/6,电子信息工程专业英语教程,27,Conflict in dictionary,A state of open, often prolonged fighting; a battle or war.战役或战争 A state of disharmony between incompatible or antithetical p
21、ersons, ideas, or interests; a clash.冲突A psychic struggle, often unconscious, resulting from the opposition or simultaneous functioning of mutually exclusive impulses, desires, or tendencies.心理挣扎 Opposition between characters or forces in a work of drama or fiction, especially opposition that motiva
22、tes or shapes the action of the plot.（戏剧或小说）冲突,2018/12/6,电子信息工程专业英语教程,28,Conflict in text,Theoretically, 992 channels can be supported in each cell, but many of them are not available, to avoid frequency conflicts with neighboring cells. 理论上讲，每个蜂窝小区可以支持992个信道；但为了避免和邻近蜂窝小区发生频率冲突，许多信道并不能使用。,2018/12/6,
23、电子信息工程专业英语教程,29,Conflict in use,conflict contest combat fight affrayThese nouns denote struggle between opposing forces for victory or supremacy. Conflict applies both to open fighting between hostile groups and to a struggle, often an inner struggle, between antithetical forces Contest can refer ei
24、ther to friendly competition or to a hostile struggle to achieve an objective: an archery contest; a spelling contest;,2018/12/6,电子信息工程专业英语教程,30,Conflict in use,conflict contest combat fight affray Combat most commonly implies an encounter between two armed persons or groups: Fight usually refers to
25、 a clash, physical or figurative, involving individual adversaries: A fight was scheduled between the world boxing champion and the challenger. Affray suggests a public fight or brawl:,2018/12/6,电子信息工程专业英语教程,31,Comparable in dictionary,Admitting of comparison with another or others:可比较的 Our house is
26、 not comparable with yours. A fire is comparable with the sun; both give light and heat. Similar or equivalent:相似或相当： A comparable car would cost far more in Europe. No horse has a speed comparable to that of his.,2018/12/6,电子信息工程专业英语教程,32,Comparable in text,TDM is comparable to the people being in
27、the middle of the room but taking turns speaking. FDM is comparable to the people being in widely separated clumps, each clump holding its own conversation at the same time as, but still independent of, the others. CDMA is comparable to everybody being in the middle of the room talking at once, but
28、with each pair in a different language.,2018/12/6,电子信息工程专业英语教程,33,Random in dictionary,Having no specific pattern, purpose, or objective:没有明确形式、目的或内容的： random movements; a random choice. Of or relating to the same or equal chances or probability of occurrence for each member of a group.随机的,2018/12/6
29、,电子信息工程专业英语教程,34,Random in text,Thus, the key to CDMA is to be able to extract the desired signal while rejecting everything else as random noise. 因此，CDMA的关键在于能够提取出希望得到的信号，而把其他信号当作随机噪声而加以抑制。,2018/12/6,电子信息工程专业英语教程,35,Random in use,random, haphazard, chance, casual Random 强调某事不是按计划发生的 The experiment
30、cannot be satisfactory because he has to use the random selection of specimens. Haphazard 表示说话或使用某物时不考虑效果 He regrerted his haphazard remarks. Chance 包含着冒险性或不确定性，或者结果是不能预知的 Without something of this kind, searching for intelligence on other planets would be like trying to meet a friend in London with
31、out a pre-arranged rendezvous and absurdly wandering the streets in the hope of a chance encounter. Casual 表示“随便的”,2018/12/6,电子信息工程专业英语教程,36,Complement in dictionary,Something that completes, makes up a whole, or brings to perfection.补充物 The quantity or number needed to make up a whole:补足 Either of
32、two parts that complete the whole or mutually complete each other.补数 An angle related to another so that the sum of their measures is 90.余角,2018/12/6,电子信息工程专业英语教程,37,Complement in text,Each station is assigned a unique m-bit code called a chip sequence. To transmit a 1 bit, a station sends its chip
33、sequence. To transmit a 0 bit, it sends the ones complement of its chip sequence. 每个（移动）站分配到唯一的一个称为“码片序列”的m位码。要传送比特“1”，就发送这个码片序列；要传送比特“0”，就发送这个码片序列的反码。,2018/12/6,电子信息工程专业英语教程,38,Complement in use,Ones complement 二进制反码 twos complement 二进制补码 complement of an angle 余角 complement of a number 余数 compleme
34、nt of a set 补集,2018/12/6,电子信息工程专业英语教程,39,Complement in use,Complement complimentComplement and compliment, though quite distinct in meaning, are sometimes confused because they are pronounced the same. Complement means something that completes or brings to perfection. The antique silver was a comple
35、ment to the beautifully set table. Compliment means an expression or act of courtesy or praise. They gave us a compliment on our beautifully set table.,2018/12/6,电子信息工程专业英语教程,40,Inverse in dictionary,Reversed in order, nature, or effect. 相反的 Of or relating to an inverse or an inverse function. 相反的Tu
36、rned upside down; inverted. 颠倒的；倒置的,2018/12/6,电子信息工程专业英语教程,41,Inverse in dictionary,The reciprocal of a designated quantity. Also called: multiplicative inverse 倒数 The negative of a designated quantity. Also called: additive inverse相反数,2018/12/6,电子信息工程专业英语教程,42,Inverse in text,A good heuristic here
37、is for each mobile station to transmit to the base station at the inverse of the power level it receives from the base station. 一个很好的思路是：每个移动站向基站发送信号的功率是接收到的基站信号功率电平的倒数。,2018/12/6,电子信息工程专业英语教程,43,Inverse in use,Reverse Transverse,2018/12/6,电子信息工程专业英语教程,44,Spectrum in dictionary,The distribution of e
38、nergy emitted by a radiant source, as by an incandescent body, arranged in order of wavelengths.光谱 The distribution of atomic or subatomic particles in a system, as in a magnetically resolved molecular beam, arranged in order of masses.能谱 A graphic or photographic representation of such a distributi
39、on.谱图,2018/12/6,电子信息工程专业英语教程,45,Spectrum in dictionary,A range of values of a quantity or set of related quantities.范围 A broad sequence or range of related qualities, ideas, or activities:系列，范围 the whole spectrum of 20th-century thought. the whole spectrum of industry,2018/12/6,电子信息工程专业英语教程,46,Spect
40、rum in text,Increasing the amount of information to be sent from b bits/sec to mb chips/sec can only be done if the bandwidth available is increased by a factor of m, making CDMA a form of spread spectrum communication (assuming no changes in the modulation or encoding techniques). 只要可用带宽提高至原来的m倍，就可
41、以将发送信息量从b 位/秒提高到mb码片/秒；这使得CDMA是一种扩频通信的形式（假定调制和编码技术没有发生变化的话）。,2018/12/6,电子信息工程专业英语教程,47,Spectrum in use,absorption spectrum 吸收光谱, 吸收频谱 electromagnetic spectrum 电磁波频谱 energy density spectrum 能量密度谱 frequency spectrum 频谱 infrared spectrum 红外线谱 phase spectrum 相位谱 power spectrum 能谱, 功率谱 power density spec
42、trum 功率密度谱 upper sideband spectrum 上边带谱,2018/12/6,电子信息工程专业英语教程,48,Parallel in dictionary,Being an equal distance apart everywhere 平行的 Having comparable parts, analogous aspects, or readily recognized similarities 相似的，相同的，对等的 the parallel lives of two contemporaries. Having the same tendency or direc
43、tion 具有相同倾向的 parallel motives and aims. Denoting a circuit or part of a circuit connected in parallel. 并联的 Of or relating to the simultaneous transmission of all the bits of a byte over separate wires 同时输送的 Of or relating to the simultaneous performance of multiple operations并行的 parallel processing.
44、,2018/12/6,电子信息工程专业英语教程,49,Parallel in dictionary,One of a set of parallel geometric figures, such as lines or planes. 平行线，平行面 One that closely resembles or is analogous to another 相似物 A comparison indicating likeness; an analogy. 类比 The condition of being parallel; near similarity or exact agreemen
45、t in particulars; parallelism. 类似 Any of the imaginary lines representing degrees of latitude that encircle the earth parallel to the plane of the equator. 纬线 An arrangement of components in a circuit that splits the current into two or more paths. Used chiefly in the phrase in parallel. 并联,2018/12/
46、6,电子信息工程专业英语教程,50,Parallel in text,In principle, given enough computing capacity, the receiver can listen to all the senders at once by running the decoding algorithm for each of them in parallel. 从理论上讲，假如具备足够的计算能力，通过并行运行解码算法，接收机就能同时听到每一个发送方。,2018/12/6,电子信息工程专业英语教程,51,Scheme in dictionary,A systemat
47、ic plan of action.系统性计划 A secret or devious plan; a plot.阴谋；计划 An impractical or unrealistic plan:不切实际的计划 An orderly combination of related parts:系统配置 A chart, a diagram, or an outline of a system or an object.系统或计划的图表、图解或大纲,2018/12/6,电子信息工程专业英语教程,52,Scheme in text,Nevertheless, CDMA is a clever sch
48、eme that is being rapidly introduced for wireless mobile communication. 但不管怎么说，CDMA是一种非常精巧的设计，并迅速地应用于无线移动通信中。,2018/12/6,电子信息工程专业英语教程,53,Scheme in use,block scheme 方框图, 方块图 classification scheme 分类表 code scheme 编码方案 color scheme 色彩组合; 色彩设计; 配色 command coding scheme 指令编码方案 decision scheme 判定方案, 判决方案 e
49、ducational scheme 教育制度 equivalent scheme 等效电路 labeling scheme 代码电路; 标号方案 proof scheme 验证方案,2018/12/6,电子信息工程专业英语教程,54,Complicate in dictionary,To make or become complex or perplexing.使复杂或令人困惑 To twist or become twisted together.使麻烦 Complex, intricate, and involved.复杂的、错综的,2018/12/6,电子信息工程专业英语教程,55,Complicate in text,CDMA also has many other complicating factors that have been glossed over here. 在这里，我们尚未谈到CDMA技术中许多其他的、令问题复杂化的因素。,
