信息科学课后答案王朔中.docx

1、信息科学课后答案王朔中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

2、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 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 provi

3、ded dialogue 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 onl

4、y 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 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

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

6、ture 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. assume B. use C。 receive D。 accept2.Each time a positive clock edge occurs, the flip-flop ch

7、anges 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 sinewave or CW modulation systems in which the modulating signal _ of a digital pulse train。 A。 made B. consisted C。 contained D. got4.In this book we

8、 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 equivalent to one or more quan

9、tum steps. A。 interruptedly B. rudely C。 abruptly D. absolutely6.We shall only be _ with logical representations, not absolute values A. interested B. caring C。 referred D. concerned（3) Choose the phrase that is closest in meaning to the underlined part。1.It is all too easy with linear circuits， whi

10、ch appear relatively 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 possib

11、le to enhance the system performanceD. which is crucial for maintaining the desired performance2.Therefore there will be a slight time delay, due to the propagation delay of the flipflops between the time one flipflop changes state and the time the next one changes state， i.e.， the change of state r

12、ipples through the 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 r

13、ipples3.Instead of 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 relati

14、onship between individual 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 elect

15、rical pulse and 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 shutdown state so

16、mewhat below a 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 t

17、o be able to track, 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 L

18、O 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 speech.A. take measure of the speech characterist

19、icsB. 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 the operating point of each stage is adjusted so tha

20、t 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 caused by transistor parameter changes8.Stability

21、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 appropriate choice of word length to represent the signals.A。 by expressing the signals with a suitable word length B。 by using a word lon

22、g enough to 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 digitall

23、y， they first have to be sampled at a specified rate and further converted to discrete amplitude samples by quantization。2.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 attenuate selected spatial frequencies， can achieve such effects as smoothing and sharpening, a

24、nd usually 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 fundamental attributes of digital circuits, however, and the necessary accuracy can be obtained in a digital version of the modulator by an

25、appropriate choice of word length to represent the signals。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 fundamental relationship between the nature of system and the periodicity of its frequency response: a continuous system has an aperiodic frequency r

26、esponse， while a discrete system has a periodic 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 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

27、号中提取出输入消息. (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. l

28、inkedC。 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， imp

29、lemented 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 leve

30、ls 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 be

31、en 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 ta

32、ke 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 entry 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 pro