信息科學(xué)課后答案,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.對于串聯(lián)諧振，電路中的電阻愈大Q值就愈低，相應(yīng)地線路電流或電路阻抗的諧振曲線也就愈平、愈寬。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.一根帶電的導(dǎo)線其外表與重量都與不帶電導(dǎo)線完全一樣。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 dialogue box, while keeping the pulse width unchanged.在波形上點(diǎn)擊鼠標(biāo)并拖動(dòng)來改變脈沖重復(fù)頻率，或者在提供的對話框中直接輸入新的周期值，而保持脈沖寬度不變。 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 not considered electronics.電子學(xué)是一門有關(guān)帶電粒子在氣體、真空或半導(dǎo)體中運(yùn)動(dòng)的科學(xué)技術(shù)。注意，在本書中粒子運(yùn)動(dòng)僅限于金屬的情況不屬于電子學(xué)。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.硬件技術(shù)在我們使用電子特性來處理信息的能力中一直起著重要作用，而軟件及數(shù)字處理方面卻沒能與硬件同步發(fā)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 varies.然而在設(shè)計(jì)得當(dāng)?shù)闹绷鞣糯笃髦校粽{(diào)節(jié)每一級(jí)的工作點(diǎn)使之在溫度變化時(shí)保持在晶體管線性區(qū)，就能在實(shí)際上消除Ico以外的晶體管參數(shù)變化所造成的影響。(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 state, 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 emphasize 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. interruptedlyB. 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 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 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 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 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 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 relationship 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 electrical 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 shut-down state somewhat 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 to 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 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 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 the 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 caused by transistor parameter changes8. 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 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 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 first have to be sampled at a specified rate and further converted to discrete amplitude samples by quantization.2. 如果要以數(shù)字方式傳輸模擬信號(hào)，首先必須以一定的頻率對信號(hào)進(jìn)行采樣，然后通過量化進(jìn)一步將它們轉(zhuǎn)換為離散的幅度樣本。Linear filters amplify or attenuate selected spatial frequencies, can achieve such effects as smoothing and sharpening, and usually form the basis of re-sampling and boundary detection algorithms.3. 線性濾波器放大或衰減選擇的空間頻率，能夠?qū)崿F(xiàn)像平滑和銳化這些效果，通常是重采樣和邊緣檢測算法的基礎(chǔ)。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 appropriate choice of word length to represent the signals.4. 不過穩(wěn)定性和可重復(fù)性是數(shù)字電路的基本性質(zhì)，在數(shù)字式調(diào)制器中必要的精度可通過適當(dāng)?shù)剡x擇代表信號(hào)的字長而獲得。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 response, while a discrete system has a periodic frequency response.5. 從系統(tǒng)性質(zhì)和它頻率響應(yīng)的周期性之間的基本關(guān)系中首先可以看到：連續(xù)系統(tǒng)有非周期性的頻率響應(yīng)，而離散系統(tǒng)有周期性的頻率響應(yīng)。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從由信道傳輸來的退化了的信號(hào)中提取出輸入消息。 (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. linkedC. 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, 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 process.A. practiced using skills generally available in the industry B. commonly performed at levels 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 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 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 provide a 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 designB. this book provides some actually working experiences about the design problemsC. this book presents some available experiences 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. 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 properly designed DC amplifier the effect of transistor parameter variation, other than Ico, 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. parameterUnit 3 Exercises(1) Translate the following sentences into Chinese.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. 一個(gè)很常用的微波測量方法是基于對駐波圖型的研究，這種駐波是由入射波和反射波之間的干涉而沿著傳輸線形成的。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. 計(jì)算表明，當(dāng)距離增大一倍時(shí)，電磁場強(qiáng)度減小6分貝；而發(fā)射功率增大一倍時(shí)，場強(qiáng)則增加3分貝。這一結(jié)果驗(yàn)證了所用算法的正確性。Like transfer of heat by conduction, convection and radiation, microwave heating can be considered as another mode of heat transfer, in which heat is produced directly at the location of the dielectric losses. 4. 就像通過傳導(dǎo)、對流、輻射來傳遞熱量一樣，微波加熱可以看作熱傳遞的另一種方式，即熱量直接產(chǎn)生于發(fā)生介電損耗的地方。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 and to return at the antenna and the receiver.5. 雷達(dá)的工作是基于對天線發(fā)出的脈沖被所要探測的目標(biāo)反射，（然后）回到天線和接收機(jī)所需時(shí)間的測量。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 desire to discover the unexpected.6. 在電路設(shè)計(jì)中使用CAD的其它動(dòng)機(jī)包括：想要驗(yàn)證用別的方法設(shè)計(jì)出來的電路；滿足好奇心或者可能是想發(fā)現(xiàn)預(yù)想不到的現(xiàn)象。后一個(gè)動(dòng)機(jī)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 repeating amplifiers is a function of the cable attenuation and the system bandwidth so that the gain provided by these amplifiers compensates for the loss introduced by the cable.7. 中繼放大器之間的間距是電纜衰減和系統(tǒng)帶寬的函數(shù)，以便這些放大器提供的增益補(bǔ)償電纜引起的損耗。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 completely rebuilt.8. 當(dāng)截止頻率不小于原始信號(hào)的最高頻率，也不大于采樣頻率和最高頻率之差，原始信號(hào)可以完整地重建。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.盡管近百年來的政治活動(dòng)是以工業(yè)時(shí)代的技術(shù)為中心的，未來的政治活動(dòng)將基于信息時(shí)代的事物，面向信息的存儲(chǔ)、保護(hù)和交換。(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 produced.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 wavelength.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 using 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 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 network 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 range 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 rays 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 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. 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 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 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 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 usually 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 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.2. 通信可以廣義地定義為從一處到另一處的信息傳遞。當(dāng)要將信息傳輸?shù)饺魏尉嚯x以外時(shí)就需要有一個(gè)通信系統(tǒng)。在通信系統(tǒng)內(nèi)部，信息的傳輸經(jīng)常通過將信息疊加或調(diào)制到作為信號(hào)載體的電磁波上來實(shí)現(xiàn)。經(jīng)調(diào)制的載波然后被傳送到要求的目的地，在那里被接收，原始信號(hào)通過解調(diào)被恢復(fù)出來。為了實(shí)現(xiàn)這一過程，已經(jīng)利用工作在射頻、微波以及毫米波頻率上的電磁載波開發(fā)了復(fù)雜的技術(shù)。不過通信也可以用光波頻段上的電磁載波來實(shí)現(xiàn)。Electronic communications is the transfer and movement of data between locations through the use of computers. An electronic communication system includes the equipment needed to support the movement of information, the communication lines and media to carry the information, the computer software and programs to control the flow of information, the personnel to plan, implement, and operate communications, and the management of all these resources. Electronic communications establishes links between people as well as computers.3. 電子通信就是通過使用計(jì)算機(jī)在不同的地點(diǎn)之間傳輸數(shù)據(jù)。一個(gè)電子通信系統(tǒng)包括：支持信息流動(dòng)所需要的設(shè)備，承載信息的通信線路和媒介，控制信息流的計(jì)算機(jī)軟件和程序，計(jì)劃、實(shí)施、操作通信系統(tǒng)的人員，以及對所有這些資源的管理。電子通信建立起人和人、計(jì)算機(jī)和計(jì)算機(jī)之間的聯(lián)系。First generation communications systems can be characterized by the use of analog transmission techniques, and the use of simple multiplex access techniques such as frequency division multiple access (FDMA). They suffered from a low user capacity, and security problems due to the simple radio interface used. Second generation systems were introduced in the early 1990s, and all use digital technology. This provided an increase in the user capacity of around three times, achieved by compressing the voice waveforms before transmission. Third generation systems are an extension on the complexity of second-generation systems and are to be introduced after the year 2000. The system capacity will be increased to over ten times original first generation systems, achieved by using complex multiplex access techniques such as code division multiplex access (CDMA), or an extension of TDMA, and by improving flexibility of services available.4. 第一代通信系統(tǒng)以模擬傳輸技術(shù)和簡單復(fù)用技術(shù)如頻分復(fù)用為特征。這些系統(tǒng)用戶容量低，而且因?yàn)槭褂煤唵蔚臒o線電接口而存在安全問題。第二代通信系統(tǒng)于20世紀(jì)90年代初開始引入，全部使用數(shù)字技術(shù)。通過在傳輸前將話音波形壓縮使得用戶容量提高了三倍。第三代通信系統(tǒng)是對第二代系統(tǒng)在復(fù)雜性方面的擴(kuò)展，預(yù)計(jì)于2000年以后啟用。通過使用復(fù)雜的復(fù)用技術(shù)如CDMA或TDMA的擴(kuò)展，并提高服務(wù)的靈活性使得系統(tǒng)容量比原來的第一代系統(tǒng)提高10倍。For each combination of communication (modulation/detection)