信息科学课后答案,王朔中[共70页]

1、科技英语课件 ExercisesUni t 1 Exer cises( 1) T ranslate the following sentences i nt o C hinese.1. As with series resonance, the greater the resistance in the circuit the lower the Q and,accordingly, the flatter and broader the resonance curve of either line current or circuitimpedance.对于串联谐振,电路中的电阻愈大 Q 值

2、就愈低,相应地线路电流或电路阻抗的谐振曲线也就愈平、愈宽。2. A wire carrying a current looks exactly the same and weighs exactly the same as it doeswhen it is not carrying a current. 一根带电的导线其外表与重量都与不带电导线完全一样。3. Click mouse on the waveform and drag it to change the pulse repetition rate, or directlyenter a new value of the perio

3、d in the provided dialogue box, while keeping the pulsewidth unchanged.在波形上点击鼠标并拖动来改变脉冲重复频率,或者在提供的对话框中直接输入新的周期值,而保持脉冲宽度不变。4. Electronics is the science and the technology of the passage of charged particles in a gas,in a vacuum, or in a semiconductor. Please note that particle motion confined within

4、 ametal only is not considered electronics. 电子学是一门有关带电粒子在气体、真空或半导体中运动的科学技术。注意,在本书中粒子运动仅限于金属的情况不属于电子学。5. Hardware technologies have played vital roles in our ability to use electronic properties toprocess information, but software and data processing aspects have not developed at thesame speed. 硬件技术在

5、我们使用电子特性来处理信息的能力中一直起着重要作用,而软件及数字处理方面却没能与硬件同步发展。6. However, in a properly designed DC amplifier the effect of transistor parameter variation,other than Ico, may be practically eliminated if the operation point of each stage isadjusted so that it remains in the linear operation range of the transistor

6、 as temperaturevaries. 然而在设计得当的直流放大器中,若调节每一级的工作点使之在温度变化时保持在晶体管线性区,就能在实际上消除 Ico 以外的晶体管参数变化所造成的影响。( 2) F ill in the blank s with the m ost appropriat e choice.1. A message signal can any amplitude value between 0 and A volts. A. assume B. use C. receive D. accept2. Each time a positive clock edge occu

7、rs, the flip-flop changes state, leading to half as many pulses at the output to the clock input. A. as B. compared C. due D. so as3. In the previous section we discussed sine-wave or CW modulation systems in which the modulating signal _ of a digital pulse train. A. made B. consisted C. contained D

8、. got4. In this book we shall emphasize the limitations imposed on the information transmitted by the system through which it was _ and shall attempt some comparison of different systems. A. put B. traveled C. passed D. viewed5. This signal either does not change, or it changes _ by an amount equiva

9、lent to one or more quantum steps.A. interruptedly B. rudely C. abruptly D. absolutely6. We shall only be _ with logical representations, not absolute valuesA. interested B. caring C. referred D. concerned( 3) C hoose the phr ase t hat is closest in mean i ng to the under lined part.1. It is all too

10、 easy with linear circuits, which appear relatively simple when compared withtodays complex logic arrangements, to ignore detailed performance parameters which can drastically reduce the expected performance.A. which has bad influence upon the system performanceB. which is important to ensure circui

11、t linearityC. which is possible to enhance the system performanceD. which is crucial for maintaining the desired performanceHMILYYLIMH 1科技英语课件 Exercises2. Therefore there will be a slight time delay, due to the propagation delay of the flip-flopsbetween the time one flip-flop changes state and the t

12、ime the next one changes state, i.e.,the change of state ripples through the counter, and these counters are therefore calledripple counters.A. the state change is propagated through the counter like ripplesB. the state changes cause ripples in the counterC. passing through the counter, the state ri

13、pple changesD. the state of the counter changes due to ripples3. Instead of triggering on each pulse, a phase lock technique examines the relative phasebetween each oscillator and many of its sync pulses and adjusts oscillator frequency sothat the average phase discrepancy is small. A. checks each o

14、scillator for many sync pulsesB. checks the phase relationship between individual oscillators and a collection of syncpulsesC. looks at the relations between the phase and the sync pulsesD. examines whether the phase is relative to the oscillator and the sync pulses4. By keeping the off state slight

15、ly below threshold, the delay between the applied electricalpulse and the resulting optical output pulse is minimized; this delay must indeed not bemore than the bit interval so that the optical pulse can accurately reproduce the inputsignal.A. ensuring that the system is off the threshold by a smal

16、l marginB. maintaining the system -doswsnhustate somewhat below a prescribed levelC. making sure the system is below its threshold so that the state is kept offD. keeping the system in a shut-down state that is under a given level with a tiny tolerance5. If the original signal is well behaved, the l

17、ocal oscillator will need very little informationto be able to track, and that information can be obtained by averaging for a long period oftime, thereby eliminating noise that could be very large.A. the LO will not require any information in order to keep trackingB. the LO will make use of tracking

18、 information that is scarce in the systemC. the LO will require some information, but not much, so that the system can trackD. the LO will use no information other than some little one to maintain tracking6. The third section describes quantization schemes that take account of the characteristics of

19、speech.A. take measure of the speech characteristicsB. take the speech characteristics into considerationC. count the speech characteristicsD. make use of the speech characteristics7. In a properly designed DC amplifier the effect of transistor parameter variation may be practically eliminated if th

20、e operating point of each stage is adjusted so that it remains in the linear operation range of the transistor as temperature varies.A. the effective variation of the transistor parametersB. the effort to change transistor parametersC. the transistor parameters that effectively changeD. the results

21、caused by transistor parameter changes8. Stability and repeatability are fundamental attributes of digital circuits, however, and thenecessary accuracy can be obtained in a digital version of the modulator by an appropriatechoice of word length to represent the signals.A. by expressing the signals w

22、ith a suitable word lengthB. by using a word long enough to describe the signalsC. by choose to characterize the signals in terms of word length appropriatelyD. by appr opri ately r epresenting the signal s to ch oose a length of wor dsU nit 2 E xer cises(1) T r anslate the fol lowi ng sen ten ces i

23、nto C hinese.1. If analog signals are to be transmitted digitally, they first have to be sampled at a specifiedrate and further converted to discrete amplitude samples by quantization.HMILYYLIMH 2科技英语课件 Exercises2. 如果要以数字方式传输模拟信号,首先必须以一定的频率对信号进行采样,然后通过量化进一步将它们转换为离散的幅度样本。 Linear filters amplify or at

24、tenuateselected spatial frequencies, can achieve such effects as smoothing and sharpening, andusually form the basis of re-sampling and boundary detection algorithms.3. 线性滤波器放大或衰减选择的空间频率,能够实现像平滑和锐化这些效果,通常是重采样和边缘检测算法的基础。 Stability and repeatability are fundamentalattributes of digital circuits, howev

25、er, and the necessary accuracy can be obtained in adigital version of the modulator by an appropriate choice of word length to represent thesignals.4. 不过稳定性和可重复性是数字电路的基本性质,在数字式调制器中必要的精度可通过适当地选择代表信号的字长而获得。 The first observation is made on the fundamentalrelationship between the nature of system and t

26、he periodicity of its frequency response: acontinuous system has an aperiodic frequency response, while a discrete system has aperiodic frequency response.5. 从系统性质和它频率响应的周期性之间的基本关系中首先可以看到：连续系统有非周期性的频率响应,而离散系统有周期性的频率响应。 The main function of thereceiver is to extract the input message signal from the

27、degraded version of thetransmitted signal coming from the channel.接收器的主要效用是从由信道传输来的退化了的信号中提取出输入消息。(2) Ch oose the wor d or phrase that is closest in meaning to the under lined par t.1. Roughly speaking, the transistor can be likened to an electronically controlled valve whereby energy applied to one

28、 connection of the valve enables energy to flow between two other connections.A. related B. linkedC. analogized D. viewed2. While third party design tools were available, there was not an effective link from the third party design tools to the layout and actual semiconductor process performance char

29、acteristics of the various ASIC manufacturers.A. WhenB. Although C. AsD. Since3. These steps, implemented with a level of skill common in the industry, almost always produce a final device that correctly implements the original design, unless flaws are later introduced by the physical fabrication pr

30、ocess.A. practiced using skills generally available in the industryB. commonly performed at levels of skilled personnel in the industryC. realized with the skillful common level in the industry D. carried out by skills commonly used in the industry4. A second major step would be to develop design sp

31、ecifications that consider the functionality of the human with the same degree of care that has been given to the rest of the system.A. develop design procedures to account for the human behavior and activitiesB. promote design arrangements and take the human factors into considerationC. make used o

32、f design steps that respect the human functionality D. draft and effect design requirements that take into account the human functionality5. Click mouse on the waveform and drag it to change the pulse repetition rate or directlyenter a new value of the period in the provided dialogue box, keeping th

33、e pulse widthunchanged.A. simply type a new period value in the given dialogue boxB. direct an entry for the new period value to the dialogue boxC. point a straightforward new period value to the dialogue box providedHMILYYLIMH 3科技英语课件 ExercisesD. enter a direction of a new period value to provide a

34、 dialogue box6. Compared with most of the textbooks at the introductory level of RF analog design, this book presents some hands-on experiences on the design issues that really work and has been proved by manufactured chips.A. this book provides some experiences at hand on the issues encountered in

35、designB. this book provides some actually working experiences about the design problemsC. this book presents some available experiences over the design problems D. this book presents some issues concerning design experiences that are handed over7. For a decade there has been a search for a programma

36、ble processor which, given the costand volume constraints, is general enough to be programmed with different algorithms. A. with controlled measures of price and magnitudeB. given the condition of risk and numberC. given the constants of charge and weightD. given the limits of price and size8. In a

37、properly designed DC amplifier the effect of transistor parameter variation, other thanIco, may be practically eliminated if the operating point of each stage is adjusted so that it remains in the linear operation range of the transistor as temperature varies.A. transistorB. amplifierC. IcoD. parame

38、terUnit 3 Exercises ( 1) T ranslate the following sentences i nt o C hinese.1. A very commonly used method of microwave measurements is based on the study of a standing wave pattern formed along the line because of the interference of incident and reflected waves.2. 一个很常用的微波测量方法是基于对驻波图型的研究,这种驻波是由入射波

39、和反射 波之间的干涉而沿着传输线形成的。 Computations show a reduction of 6dB in the EM field intensity with the distance doubled, and an increase of 3dB in the intensity with the transmitted power doubled. This result provides verification to the algorithm used.3. 计算表明,当距离增大一倍时,电磁场强度减小 6 分贝；而发射功率增大一倍时, 场强则增加 3 分贝。这一结果

40、验证了所用算法的正确性。 Like transfer of heat byconduction, convection and radiation, microwave heating can be considered as anothermode of heat transfer, in which heat is produced directly at the location of the dielectriclosses.4. 就像通过传导、对流、辐射来传递热量一样,微波加热可以看作热传递的另一种方 式,即热量直接产生于发生介电损耗的地方。 Operation of the rad

41、ar is based on themeasurement of the time it takes for a pulse transmitted from an antenna to get reflectedby the object to be detected and to return at the antenna and the receiver.5. 雷达的工作是基于对天线发出的脉冲被所要探测的目标反射, （然后）回到天线和接 收机所需时间的测量。 Other motivations for using CAD in circuit design includes the wi

42、sh to acquire confidence in a design that was accomplished by other means, and, not least in importance, a sense of curiosity or perhaps a desire to discover the unexpected.6. 在电路设计中使用 CAD 的其它动机包括： 想要验证用别的方法设计出来的电路； 满 足好奇心或者可能是想发现预想不到的现象。后一个动机并非是最不重要的。 （取得信心, 并非最不重要, 意料之外的事） The spacing between the

43、repeating amplifiers is afunction of the cable attenuation and the system bandwidth so that the gain provided bythese amplifiers compensates for the loss introduced by the cable.7. 中继放大器之间的间距是电缆衰减和系统带宽的函数,以便这些放大器提供的增益补偿电缆引起的损耗。 When the cut-off frequency is no less than the maximal frequencyof the o

44、riginal signal, nor is it greater than the difference between the sampling frequencyand the maximal frequency, the original signal may be completely rebuilt.8. 当截止频率不小于原始信号的最高频率,也不大于采样频率和最高频率之差,原始信号可以完整地重建。 While the politics of the last one hundred years centered aroundIndustrial Age technology, th

45、e politics of the future will be based on Information Ageconcerns oriented towards the storage, protection and exchange of information.HMILYYLIMH 4科技英语课件 Exercises尽管 近百年来的政 治活动是以工 业时代的技术 为中心的,未 来的政治活动 将基于信息时 代的事 物,面向信息 的存储、保护和 交换。( 2) C hoose the wor d or phr ase that is closest inmeaning to the und

46、er lined part .1. If these other charges and currents are comparable in size to the sources producing the above electromagnetic field, then a new net electromagnetic field will be produced. A. make comparison with the size of the sourcesB. are compared with the size of the sources C. have similar si

47、ze to the sourcesD. take a common size of the sources2. This range of wavelengths has led many to question the naming convention used for microwaves as the name suggests a micrometer wavelength.A. has raised many questions about the naming habitB. has caused many people to challenge the naming rules

48、C. has led many questions of the naming conventionD. has resulted in many problems in the naming tradition3. NASA worked in the 1970s and early 1980s to research the possibilities of using SolarPower Satellite (SPS) systems with large solar arrays that would beam power down to the Earth s surfavciea

49、 microwaves.A. shed solar energy to the Earths surface from the satelliteB. set the satellite down to the Earth s surface with powerC. shut down the power on (to) the Earth s surface from the satelliteD. switch off power to the Earth s surface from the satellite4. As DoD urgently wanted military com

50、mand and control networks that could survive a nuclear war, ARPA was charged with inventing a technology that could get data to its destination reliably even if arbitrary parts of the network disappeared without warning as a result of a nuclear attack.A. win a nuclear warB. be used in preparation of

51、 a nuclear war C. avoid a nuclear warD. be still operational after a nuclear war5. At the present, state of the art microwave amplifiers and oscillator tubes can operate in a frequency range up to 40GHz and solid-state microwave devices up to 100GHz. A. recent and most advancedB. high tech relatedC.

52、 sophisticatedD. artistically manufactured6. In such a fiber rays traveling at larger angles with respect to the axis have to traverse a longer path and hence take a longer time than those rays which propagate with smaller angles to the axis.A. have transmitted over a longer distance B. are bound to

53、 treat a longer wayC. must travel through a longer route D. must deal with a longer trace7. By keeping the off state slightly below threshold, the delay between the applied electricalpulse and the resulting optical output pulse is minimized; this delay must indeed not bemore than the bit interval so

54、 that the optical pulse can accurately reproduce the inputsignal.A. this delay must indeed be no more than one internal bitB. indeed, this delay must exceed the bit of intervalC. as a matter of fact, this delay interval must be a little bit lessD. this delay must indeed be kept less than the spacing

55、 between data bits8. Computations show a reduction of 6dB in the EM field intensity with the distance doubled,and an increase of 3dB in the intensity with the transmitted power doubled. This resultprovides verification to the algorithm used.A. that, with a 6dB reduction, the EM field intensity is tw

56、ice as strongB. that the EM field intensity is decreased by 6dB as the range is doubledC. that, in the EM field, intensity with double distance leads to a 6dB reductionHMILYYLIMH 5科技英语课件 ExercisesD. a 6dB intensi ty redu cti on causes a double di st ance in the EM f ieldU nit 4 Exer cises(1) T r ans

57、late the fol lowi ng p assa ges int o C hinese.1. Communication may be broadly defined as the transfer of information from one point to another. When the information is to be conveyed over any distance a communication system is usually required. Within a communication system the information transfer

58、 is frequently achieved by superimposing or modulating the information on to an electromagnetic wave which acts as a carrier for the information signal. This modulated carrier is then transmitted to the required destination where it is received and the original information signal is obtained by demodulation. Sophisticated techniques have been developed for this process by using electromagnetic carrier waves operating at