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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,2020/8/8,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,2020/8/8,电子信息工程专业英语教程,3,Terminology TDM 时分复用 FDM 频分

2、复用 PCM 脉冲编码调制 PCS 个人通信系统 spread spectrum communication 扩频通信,Backgrounds,2020/8/8,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,2020/8/8,电子信息工程专业英语教程,5,D-AMPS is the second gener

3、ation 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,2020/8/8,电子信息工程专业英语教程,6,Figure 4.2. (

4、a) A D-AMPS channel with 3 users. (b) A D-AMPS channel with 6 users.,D-AMPS The Digital Advanced Mobile Phone System,2020/8/8,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 by T

5、DM into time slots shared by multiple mobiles.,GSMThe Global System for Mobile Communications,2020/8/8,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,GSMThe Gl

6、obal System for Mobile Communications,2020/8/8,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.,GSMThe Global System for Mobile Communications,2020/8/8,电子信息工程专业英语教程,10,Figure4.4. A portion of the GSM framing structure.,GSMThe Global System for

7、Mobile Communications,2020/8/8,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,CDMACode Division Multiple Access,2020/8/8,电子信息工程专业英语教程,12,Vocabulary modulation, approximation, conflict, comparable, random, compl

8、ement, inverse, spectrum, parallel, scheme, complicate Structure Reading/writing techniques,Language in use,2020/8/8,电子信息工程专业英语教程,13,Vocabulary,2020/8/8,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. The variation of a

9、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 communication facilit

10、ies. A method of representing data in magnetizable surface storage; for example, “modified frequency modulation”.,2020/8/8,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 more sophisticated th

11、an 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。,2020/8/8,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(冲编)码调制 differential

12、pulse code modulation 差值脉冲编码调制,2020/8/8,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,2020/8/8,电子信息工程专业英语教程,18,Modulation in use,incidental phase modulation 寄生调相 pulse

13、-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,2020/8/8,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,2020/8/8,电子信息工程专业英语教程,20,Approximation in text

14、,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。,2020/8/8,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 differential approximation 微分逼近

15、digital approximation 数值逼近 engineering approximation 工程近似法 exponential approximation 指数近似,2020/8/8,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 集中参数近似 rational function app

16、roximation 有理函数逼近,2020/8/8,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, especially a movie theater

17、 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,2020/8/8,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 digitization and compress

18、ion 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。,2020/8/8,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 multiplex 频率多工通信 frequency-d

19、ivision 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,2020/8/8,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, half duplex) In data c

20、ommunication, pertaining to a simultaneous two-way independent transmission in both directions. Complex,2020/8/8,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 persons, ideas, or inte

21、rests; 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 motivates or shapes the a

22、ction of the plot. (戏剧或小说)冲突,2020/8/8,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。,2020/8/8,电子信息工程专业英语教程,29,Conf

23、lict in use,conflict contest combat fight affray These 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 either to friendly co

24、mpetition or to a hostile struggle to achieve an objective: an archery contest; a spelling contest;,2020/8/8,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 a clash, physical o

25、r figurative, involving individual adversaries: A fight was scheduled between the world boxing champion and the challenger. Affray suggests a public fight or brawl:,2020/8/8,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 not comparable with

26、 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.,2020/8/8,电子信息工程专业英语教程,32,Comparable in text,TDM is comparable to the people being in the middle of the ro

27、om 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 with each pair in a

28、different language.,2020/8/8,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,2020/8/8,电子信息工程专业英语教程,34,Ran

29、dom 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。,2020/8/8,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 cannot be satisfactor

30、y 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 without a pre-arranged re

31、ndezvous and absurdly wandering the streets in the hope of a chance encounter. Casual 表示“随便的”,2020/8/8,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 two parts that compl

32、ete 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,2020/8/8,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 sequence. To transm

33、it 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。,2020/8/8,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 complement of a set 补集,2020/

34、8/8,电子信息工程专业英语教程,39,Complement in use,Complement compliment Complement 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 complement to the beautifu

35、lly set table. Compliment means an expression or act of courtesy or praise. They gave us a compliment on our beautifully set table.,2020/8/8,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 Turned upside down; in

36、verted. 颠倒的;倒置的,2020/8/8,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,2020/8/8,电子信息工程专业英语教程,42,Inverse in text,A good heuristic here is for each mobile st

37、ation 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。,2020/8/8,电子信息工程专业英语教程,43,Inverse in use,Reverse Transverse,2020/8/8,电子信息工程专业英语教程,44,Spectrum in dictionary,The distribution of energy emitted by a radi

38、ant 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 distribution. 谱图,2020/8/8,电子信息工

39、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,2020/8/8,电子信息工程专业英语教程,46,Spectrum in text,Increasi

40、ng 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,就可以将发送信息量从b 位/秒提高到mb码片

41、/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)。,2020/8/8,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 spectrum 功率密度谱 upper side

42、band spectrum 上边带谱,2020/8/8,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 direction 具有相同倾向的 parallel

43、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.,2020/8/8,电子信息工程专业英语教程

44、,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 agreement in particulars; paral

45、lelism. 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,2020/8/8,电子信息工程专业英语教程,50,Parall

46、el 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。,2020/8/8,电子信息工程专业英语教程,51,Scheme in dictionary,A systematic plan of action. 系统性计划 A se

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