科技英语课件Unit1-20+rcises

1、Unit 1 Exercises(1) Translate the following sentences into Chinese.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 circuit impedance.对于串联谐振，电路中的电阻愈大Q值就愈低，相应地线路电流或电路阻抗的谐振曲线也就

2、愈平、愈宽。2. A wire carrying a current looks exactly the same and weighs exactly the same as it does when 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 directly enter a new value of the period in the provided dial

3、ogue box, while keeping the pulse width 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 a metal only is no

4、t 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 to process information, but software and data processing aspects have not developed at the same speed.硬件技术在我们使用电子特性来处理信息的能力中一

5、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 is adjusted so that it remains in the linear operation range of the transistor as temperature

6、varies.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) Fill in the blanks with the most appropriate choice.1. A message signal can any amplitude value between 0 and A volts.A. assumeB. useC. receiveD. accept2. Each time a positive clock edge occurs, the flip-flop changes s

7、tate, leading to half as many pulses at the output to the clock input.A. asB. comparedC. dueD. 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. madeB. consistedC. containedD. got4. In this book we shall empha

8、size the limitations imposed on the information transmitted by the system through which it was _ and shall attempt some comparison of different systems.A. putB. traveledC. passedD. viewed5. This signal either does not change, or it changes _ by an amount equivalent to one or more quantum steps.A. in

9、terruptedlyB. rudelyC. abruptlyD. absolutely6. We shall only be _ with logical representations, not absolute valuesA. interestedB. caringC. referredD. concerned(3) Choose the phrase that is closest in meaning to the underlined part.1. It is all too easy with linear circuits, which appear relatively

10、simple when compared with todays complex logic arrangements, to ignore detailed performance parameters which can drastically reduce the expected performance.A. which has bad influence upon the system performance B. which is important to ensure circuit linearityC. which is possible to enhance the sys

11、tem performanceD. which is crucial for maintaining the desired performance2. Therefore there will be a slight time delay, due to the propagation delay of the flip-flops between the time one flip-flop changes state and the time the next one changes state, i.e., the change of state ripples through the

12、 counter, and these counters are therefore called ripple counters.A. the state change is propagated through the counter like ripples B. the state changes cause ripples in the counterC. passing through the counter, the state ripple changesD. the state of the counter changes due to ripples3. Instead o

13、f triggering on each pulse, a phase lock technique examines the relative phase between each oscillator and many of its sync pulses and adjusts oscillator frequency so that the average phase discrepancy is small.A. checks each oscillator for many sync pulsesB. checks the phase relationship between in

14、dividual oscillators and a collection of sync pulses C. 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 slightly below threshold, the delay between the applied electrical pulse and

15、the resulting optical output pulse is minimized; this delay must indeed not be more than the bit interval so that the optical pulse can accurately reproduce the input signal.A. ensuring that the system is off the threshold by a small marginB. maintaining the systems shut-down state somewhat below a

16、prescribed levelC. making sure the system is below its threshold so that the state is kept off D. 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 local oscillator will need very little information to be able to t

17、rack, and that information can be obtained by averaging for a long period of time, 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 information that is scarce in the systemC. the LO will require

18、 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 speech.A. take measure of the speech characteristicsB. take th

19、e 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 the operating point of each stage is adjusted so that it remains

20、 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 caused by transistor parameter changes8. Stability and repeata

21、bility are fundamental attributes of digital circuits, however, and the necessary accuracy can be obtained in a digital version of the modulator by an appropriate choice of word length to represent the signals.A. by expressing the signals with a suitable word length B. by using a word long enough to

22、 describe the signalsC. by choose to characterize the signals in terms of word length appropriatelyD. by appropriately representing the signals to choose a length of wordsUnit 2 Exercises (1) Translate the following sentences into Chinese.1. If analog signals are to be transmitted digitally, they fi

23、rst have to be sampled at a specified rate and further converted to discrete amplitude samples by quantization.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。2. Linear filters amplify or attenuate selected spatial frequencies, can achieve such effects as smoothing and sharpening, and usuall

24、y form the basis of re-sampling and boundary detection algorithms. 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。3. Stability and repeatability are fundamental attributes of digital circuits, however, and the necessary accuracy can be obtained in a digital version of the modulator by an appropri

25、ate choice of word length to represent the signals.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。4. The first observation is made on the fundamental relationship between the nature of system and the periodicity of its frequency response: a continuous system has an aperiodic frequency response

26、, while a discrete system has a periodic frequency response.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。5. The main function of the receiver is to extract the input message signal from the degraded version of the transmitted signal coming from the channel.接收器的主要功能是从由信道传输来的退化了的信号中提取出输

27、入消息。 (2) Choose the word or phrase that is closest in meaning to the underlined part.1. Roughly speaking, the transistor can be likened to an electronically controlled valve whereby energy applied to one connection of the valve enables energy to flow between two other connections.A. relatedB. linked

28、C. analogizedD. 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 characteristics of the various ASIC manufacturers.A. WhenB. AlthoughC. AsD. Since3. These steps, implem

29、ented 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 process.A. practiced using skills generally available in the industry B. commonly performed at levels

30、of skilled personnel in the industryC. realized with the skillful common level in the industryD. carried out by skills commonly used in the industry4. A second major step would be to develop design specifications that consider the functionality of the human with the same degree of care that has been

31、 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 of design steps that respect the human functionalityD. draft and effect design requirements that take

32、 into account the human functionality 5. Click mouse on the waveform and drag it to change the pulse repetition rate or directly enter a new value of the period in the provided dialogue box, keeping the pulse width unchanged.A. simply type a new period value in the given dialogue boxB. direct an ent

33、ry for the new period value to the dialogue boxC. point a straightforward new period value to the dialogue box providedD. enter a direction of a new period value to provide a dialogue box6. Compared with most of the textbooks at the introductory level of RF analog design, this book presents some han

34、ds-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 designB. this book provides some actually working experiences about the design problemsC. this book presents some available ex

35、periences over the design problemsD. this book presents some issues concerning design experiences that are handed over7. For a decade there has been a search for a programmable processor which, given the cost and volume constraints, is general enough to be programmed with different algorithms.A. wit

36、h 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 properly designed DC amplifier the effect of transistor parameter variation, other than Ico, may be practically eliminated if t

37、he 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. parameterUnit 3 Exercises(1) Translate the following sentences into Chinese.1. A very commonly used method of microwave measurement

38、s is based on the study of a standing wave pattern formed along the line because of the interference of incident and reflected waves.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和反射波之间的干涉而沿着传输线形成的。2. Computations show a reduction of 6dB in the EM field intensity with the distance doubled, and an increase of 3dB

39、 in the intensity with the transmitted power doubled. This result provides verification to the algorithm used.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。这一结果验证了所用算法的正确性。3. Like transfer of heat by conduction, convection and radiation, microwave heating can be considered as another mode of heat tra

40、nsfer, in which heat is produced directly at the location of the dielectric losses. 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。4. Operation of the radar is based on the measurement of the time it takes for a pulse transmitted from an antenna to get reflected by the object to be detected

41、 and to return at the antenna and the receiver.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。5. Other motivations for using CAD in circuit design includes the wish to acquire confidence in a design that was accomplished by other means, and, not least in importance, a sense of curiosity or perhaps a

42、 desire to discover the unexpected.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）6. The spacing between the repeating amplifiers is a function of the cable attenuation and the system bandwidth so that the gain provided by these amplifiers compensates for

43、the loss introduced by the cable.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。7. When the cut-off frequency is no less than the maximal frequency of the original signal, nor is it greater than the difference between the sampling frequency and the maximal frequency, the original signal may be comple

44、tely rebuilt.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。8. While the politics of the last one hundred years centered around Industrial Age technology, the politics of the future will be based on Information Age concerns oriented towards the storage, protection and exchange of information.尽管近百年来的政

45、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) Choose the word or phrase that is closest in meaning to the underlined 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 produc

46、ed.A. make comparison with the size of the sources B. are compared with the size of the sourcesC. have similar size 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 wave

47、length.A. has raised many questions about the naming habitB. has caused many people to challenge the naming rulesC. 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 usin

48、g Solar Power Satellite (SPS) systems with large solar arrays that would beam power down to the Earths surface via microwaves.A. shed solar energy to the Earths surface from the satellite B. set the satellite down to the Earths surface with powerC. shut down the power on (to) the Earths surface from

49、 the satelliteD. switch off power to the Earths surface from the satellite4. As DoD urgently wanted military command 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 netw

50、ork disappeared without warning as a result of a nuclear attack.A. win a nuclear warB. be used in preparation of a nuclear warC. 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 rang

51、e up to 40GHz and solid-state microwave devices up to 100GHz.A. recent and most advancedB. high tech relatedC. 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 r

52、ays which propagate with smaller angles to the axis.A. have transmitted over a longer distanceB. are bound to treat a longer way C. must travel through a longer routeD. must deal with a longer trace7. By keeping the off state slightly below threshold, the delay between the applied electrical pulse a

53、nd the resulting optical output pulse is minimized; this delay must indeed not be more than the bit interval so that the optical pulse can accurately reproduce the input signal.A. this delay must indeed be no more than one internal bitB. indeed, this delay must exceed the bit of intervalC. as a matt

54、er of fact, this delay interval must be a little bit lessD. this delay must indeed be kept less than the spacing 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. T

55、his result provides verification to the algorithm used.A. that, with a 6dB reduction, the EM field intensity is twice 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 reductionD. a 6dB intensity

56、 reduction causes a double distance in the EM fieldUnit 4 Exercises (1) Translate the following passages into Chinese.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 u

57、sually required. Within a communication system the information transfer 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

58、 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 radio frequencies as well as microwave and millimeter wave frequencies. However, communication may also be achieved by using an electromagnetic carrier that is selected from the optical range of frequencies.通信可以广义地定义为从一处到另一处的信息传递。当要将信息传输到任何距离以外时就需要有一个通