PART1電路和電子工程基礎A電路 英語專業(yè)

1、PART 1電路和電子工程基礎 A 電路1 In the case of a resistor, the voltage-current relationship is given by Ohms law, which states that the voltage across the resistor is equal to the current through the resistor multiplied by the value of the resistance.就電阻來說，電壓電流的關系由歐姆定律決定。歐姆定律指出：電阻兩端的電壓等于電阻上流過的電流乘以電阻值。2It may

2、be that the inductor voltage rather than the current is the variable of interest in the circuit.或許在電路中，人們感興趣的變量是電感電壓而不是電感電流。B 三相電路1 Viewed in this light, it will be found that the analysis of three-phase circuits is little more difficult than that of single-phase circuits. 這樣看來，三相電路的分析比單相電路的分析難不了多少。

3、2 At unity power factor，the power in a single-phase circuit is zero twice each cycle在功率因數(shù)為1時，單相電路里的功率值每個周波有兩次為零。3 It should be noted that if the polarity of point A with respect to N ( ) is assumed for the positive half-cycle, then when used in the same phasor diagram should be drawn opposite to, or

4、 180 out of phase with, .應該注意，如果把A點相對于N的極性（ ）定為正半周，那么 在用于同一相量圖中時就應該畫得同 相反，即相位差為180。A 運算放大器1 One problem with electronic devices corresponding to the generalized amplifiers is that the gains, AU or AI, depend upon internal properties of the two-port system.對應于像廣義放大器這樣的電子裝置，一個問題就是增益 AU 或者AI ，它們?nèi)Q于兩輸入端

5、系統(tǒng)的內(nèi)部特性。2 This is one of the key features of Op-Amp designthe action of the circuit on signals depends only upon the external elements which can be easily varied by the designer and which do not depend upon the detailed character of the Op-Amp itself.這是運算放大器設計的重要特征之一在信號作用下，電路的動作僅取決于能夠容易被設計者改變的外部元件，而

6、不取決于運算放大器本身的細節(jié)特性。B 晶體管1 Put very simply a semiconductor material is one which can be “doped” to produce a predominance of electrons or mobile negative charges (N-type); or “holes” or positive charges (P-type).簡單地說，半導體是這樣一種物質，它能夠通過“摻雜”來產(chǎn)生多余的電子，又稱自由電子（N型）；或者產(chǎn)生“空穴”，又稱正電子（P型）。2 TO1 is the original trans

7、istor shapea cylindrical “can” with the three leads emerging in triangular pattern from the bottom. Looking at the base, the upper lead in the “triangle” is the base, the one to the right (marked by a color spot) the collector and the one to the left the emitter.TO1是最早的一種晶體管形狀即一個帶有三個引腳的圓柱體“外罩”，這三個引腳

8、在底部形成三角狀。首先要注意的是，“三角形”上面的引腳是基極，其右面的引腳（由一個彩色點標出）為集電極，其左面的引腳為發(fā)射極。 A 邏輯變量與觸發(fā)器1 We shall now briefly discuss the relevance of such terminology, and in so doing we shall bring out the special aptness of the designations “true” and “false” to identify the possible values of a variable. 現(xiàn)在我們將簡要地討論一下這些術語之間的

9、關聯(lián)，并在此過程中闡明用標示“真”和“假”來識別一個變量的可能值的特殊用途。2 Just as other algebras deal with variables which have a numerical significance, Boolean algebra deals with propositions and is an effective tool for analyzing the relationships between propositions which allow only two mutually exclusive alternatives.和其他處理有數(shù)字意

10、義的變量的代數(shù)一樣，布爾代數(shù)處理的是命題，而且布爾代數(shù)對于分析僅有兩個互反變量命題之間的關系是一種有效的工具。3 There is a generally prevailing attitude in digital systems to view logic 0 as a basic, undisturbed, unperturbed, quiescent state and to view the logic 1 state as the excited, active, effective state, i.e., the state arrived at “after somethin

11、g has happened.”在數(shù)字系統(tǒng)中，普遍的觀點是把邏輯0看成一個基本的、無干擾的、穩(wěn)定的、靜止的狀態(tài)，把邏輯1看成一個激勵的、活躍的、有效的狀態(tài)，也就是說，這種狀態(tài)是發(fā)生在“某種操作動作之后”。B 二進制數(shù)字系統(tǒng)1 Such devices operate well in a two-state or binary system, using conduction and cutoff as the operating states, and as a result the binary number system is generally employed in internal

12、operations in digital computers.將導通和關斷作為工作狀態(tài)，這樣的裝置可以在兩態(tài)即二進制系統(tǒng)中運行，因此數(shù)字計算機中的內(nèi)部操作一般采用二進制系統(tǒng)。2 Given the basic idea of a chain of positive and negative, or positive and zero, or zero and negative pulses as representing binary 1s and 0s, there are many possible codes in which the pulses might be transmitt

13、ed.給出一串正脈沖和負脈沖，或正脈沖和零，或者零和負脈沖來表示二進制的1及0時，就會有許多這些脈沖可以傳遞的碼。A 功率半導體器件1 Power diodes provide uncontrolled rectification of power and are used in applications such as electroplating, anodizing, battery charging, welding, power supplies (DCand AC), and variable-frequency drives.電力二極管提供不可控的整流電源，這些電源有很廣的應用，

14、如：電鍍、電極氧化、電池充電、焊接、交直流電源和變頻驅動。 2 A gate turn-off thyristor (GTO), as the name indicates, is basically a thyristor-type device that can be turned on by a small positive gate current pulse, but in addition，has the capability of being turned off by a negative gate current pulse門極可關斷晶閘管，顧名思義，是一種晶閘管類型的器件。

15、同其他晶閘管一樣，它可以由一個小的正門極電流脈沖觸發(fā)，但除此之外，它還能被負門極電流脈沖關斷。3 Such a gate current pulse of very short duration and very large di/dt has small energy content and can be supplied by multiple MOSFETs in parallel with ultra-low leakage inductance in the drive circuit.這樣一個持續(xù)時間非常短、di/dt非常大、能量又較小的門極電流脈沖可以由多個并聯(lián)的MOSFET來提

16、供，并且驅動電路中的漏感要特別低。 B 電力電子變換器1 The efficiency of the rectifiers is very high, typically in the vicinity of 98%, because device conduction loss is low and switching loss is practically negligible.由于器件開通時損耗低，且其開關損耗幾乎可忽略不計，故該類整流器的效率很高，典型值約為98。2 A variable voltage source can be converted to a variable cur

17、rent source by connection a large inductance in series and controlling the voltage within a feedback current control loop.通過串聯(lián)大電感，可變電壓源可以在電流反饋控制回路的控制下轉換為可變電流源。A 直流電機分類1 Each of these motors has different characteristics due to its basic circuit arrangement and physical properties.每種類型的電動機由于其基本電路的不同而

18、具有不同的特征和物理特性。2 The only difference, in most cases, is that the generator acts as a voltage source while the motor functions as a mechanical power conversion device.很多情況下，二者的唯一區(qū)別在于發(fā)電機常作為電壓源，而電動機常作為機械能轉換裝置。3 A decrease in field current reduces the strength of the electromagnetic field. When the field

19、flux is decreased, the armature will rotate faster, due to reduced magnetic-field interaction.勵磁電流的減小會使磁場減弱。當磁通減少時，轉子會由于與減弱的磁場相互作用而加速旋轉。B 直流傳動的閉環(huán)控制1 Any positive speed error, caused by either an increase in the speed command or an increase in the load torque, produces a higher current reference Ia*.

20、由速度給定或負載轉矩的增加所引起的任何正的速度偏差，都會產(chǎn)生更大的參考電流值Ia*。2 The speed error is corrected at the maximum permissible armature current until the speed error becomes small and the current limiter comes out of saturation.在最大允許電樞I下糾正速度偏差，直到速度偏差減小且限流裝置退出飽和狀態(tài)。A 交流機1 Neglecting the effect of slots and space harmonics due t

21、o non-ideal winding distribution, it can be shown that a sinusoidal three-phase balanced power supply in the three-phase stator winding creates a synchronously rotating magnetic field.如果忽略槽和由于非理想分布的繞組產(chǎn)生的空間諧波的影響，可以證明，在三相定子繞組中能以三相對稱電源建立一個同步旋轉的旋轉磁場。2 The rotor winding will be subjected to a sweeping ma

22、gnetic field, and have inducing current in the short-circuited rotor.轉子繞組切割磁場，就會在短路的轉子中產(chǎn)生感應電流。 3 This is in contrast to a machine with a cylindrical rotor structure having a uniform air gap (such as an induction motor), defined as a nonsalient pole machine.與其(凸極式同步機)對應的另一種電機是有均勻氣隙的圓柱體形轉子結構的電機(與異步機相似

23、)，定義為隱極式同步電機。4 For example, the stator-pole pair A-A is energized when the rotor pole-pair a-a approaches it to produce the torque by magnetic pull, but is de-energized when pole alignment occurs.例如，當轉子極對a-a接近定子極對A-A時，定子極對A-A被通電，通過磁拉力產(chǎn)生轉矩，當兩個極對重合時，定子極對A-A斷電。 B 感應電機傳動裝置1 However, as the frequency is

24、increased, the machine airgap flux falls causing low developed torque capability.然而隨著頻率增加，電機的氣隙磁通下降，導致產(chǎn)生的轉矩降低。2 In a well-designed PWM drive, the commutation frequency should be increased as permitted by the devices so as to obtain a good balance between the increase of inverter loss and decrease of

25、 machine loss.在設計完善的PWM傳動系統(tǒng)中，應在器件允許的條件下增加換相頻率，以便在逆變器損耗的增加和電機損耗的降低之間找到一個合適的平衡點。A 電力系統(tǒng) 1 In cities and other areas where open lines create a safety hazard or are considered unattractive, insulated underground cables are used for distribution.在城市和其它地區(qū)，明線存在安全隱患或者被認為影響美觀，所以使用絕緣地下電纜進行配電。2 Each utility tha

26、t agrees to share gains an increased reserve capacity, use of larger, more efficient generators, and the ability to respond to local power failures by obtaining energy from a linking grid.同意共享的每個電力企業(yè)可以獲得不斷增加的儲備功率，使用更大、效率更高的發(fā)電機，從電網(wǎng)中獲取電能以應對局部電力故障。3 Inductance and capacitance react with a tendency to n

27、ullify one another.電感和電容的作用能相互抵消。B 電力系統(tǒng)自動化 1 Metering values such as demand and peak are saved within the meter to create historical information about the activity of the power system.測量值，如需求量和峰值，可以保存在儀表中，用于創(chuàng)建電力系統(tǒng)運行的歷史信息。2 Substation integration refers to combining data from the IEDs local to a subs

28、tation so that there is a single point of contact in the substation for all of the I&C data.變電站集成指的是將局部和整個變電站的IED數(shù)據(jù)進行組合，于是對于變電站內(nèi)所有I&C數(shù)據(jù)，只有一個單聯(lián)系點。 3 The communications industry uses the term client/server for a device that acts as a master, or client, retrieving data from some devices and then acts a

29、s a slave, or server, sending this data to other devices.通信行業(yè)對設備使用術語客戶/服務器， 該設備作為主設備或客戶從其它設備得到數(shù)據(jù)，然后作為從設備或服務器向其它設備發(fā)送數(shù)據(jù)。PART 2 控制理論 A 控制的世界 1 The reaction time of a human pilot is too slow to enable him or her to fly an aircraft with a lightly damped Dutch roll mode without a yaw damper system.飛行員的反應速

30、度太慢，如果不附加阻尼偏航系統(tǒng)，飛行員就無法通過輕微阻尼的側傾轉向方式來駕駛飛機。2 Since the output is fed back in a functional form determined by the nature of the feedback elements and then subtracted from the input因為輸出會以由反饋部件特性決定的函數(shù)形式反饋回來，然后從輸入中減去B 傳遞函數(shù)和拉普拉斯變換1 The designer quickly becomes adept in relating changes in the Laplace domai

31、n to behavior in the time domain without actually having to solve the system equations.設計人員很快就會熟練地把拉普拉斯域的變化與時域狀態(tài)聯(lián)系起來，而不需真地解系統(tǒng)方程（時域）。A 穩(wěn)定性和時域響應 1 The table is continued horizontally and vertically until only zeros are obtained.這張表向水平（向右）垂直（向下）方向延伸，直到得到的都是零為止。B 穩(wěn)態(tài) 1 the principle of superposition hold

32、s, 疊加原理成立，2 , thus eliminating the velocity error, and by being introduced ahead of the point of entry of the disturbance into the system, eliminates the steady-state error resulting from a step in the disturbance.，這樣通過在系統(tǒng)擾動進入點之前引入（積分環(huán)節(jié)），可消除由擾動輸入中的階躍（成分）導致的穩(wěn)態(tài)誤差。A 根軌跡 1 as any single parameter, such

33、as a gain or time constant, is varied from zero to infinity.當任意單一參數(shù)，如增益或時間常數(shù)，從零變到無窮時。2 These effects increase in strength with decreasing distance.隨著到原點距離的減小，它們的作用強度會增加。此處distance指零（極）點到原點的距離。3 Ignoring for the weaker effect of the added pole, which is often placed at 10 times the distance to the or

34、igin, the zero忽略常被置于10倍于零點到原點距離處的附加極點的微弱作用，零點B 頻率相應方法：奈氏圖1 The wind loading of a tracking radar antenna, for example, results from a mean velocity component that varies with time plus superimposed random gusts.例如，跟蹤雷達天線的風力負載是由一個隨時間變化的平均速度成分與疊加的隨機陣風組成的。2 , it is only approximate and is subject to mis

35、interpretation. 只是近似的而且容易判斷錯誤。3 It is also the negative phase shift (i.e., clockwise rotation) of KZ(s)/P(s) which will make the curve pass through -1.它也是能使曲線通過-1點的KZ(s)/P(s)的負相位移動（即順時針旋轉）的角度。A 頻率響應法：波特圖 1 This is also true for the leads corresponding to the simple and quadratic lag below.對應于后面的一次和二

36、次滯后的超前環(huán)節(jié)也是這樣。2 To ensure a specified attenuation (reduction) of noise components in the input above a certain frequency should be below a certain level.為保證對輸入中高于一定頻率的噪聲成分指定的衰減，（伯德圖中M）應低于某一水平。B 非線性控制系統(tǒng)1 Instead, a number of techniques exist, each of limited purpose and limited applicability.有幾種技術存在，但

37、有各自限定的目的和限定的適用范圍。2 , or due to overlap of the lands on a hydraulic control valve spool over the ports to the cylinder.，或由于液壓控制閥柱上的擋圈與通向液壓缸的出口的重疊。3 , an initial condition or input outside the limit cycle leads to an unstable transient growth while transients following a sufficiently small disturbance

38、 decay to zero.，當暫態(tài)響應跟隨一個足夠小的擾動向零衰減的時候，一個在極限環(huán)外的初始條件或輸入會導致一種不穩(wěn)定的暫態(tài)增長。A 現(xiàn)代控制理論簡介 1 The transition from simple approximate models, which are easy to work with, to more realistic models produces two effects.從易于處理的簡單近似模型到實際一些的模型的轉換存在兩方面問題。2 It provides an ideal formulation for computer implementation and

39、 is responsible for much of the progress in optimization theory.它（現(xiàn)代控制理論）為計算機實現(xiàn)提供了理想的公式化方法，并對最優(yōu)化理論的發(fā)展起了重要作用。3 As far as the state at t1 is concerned, it makes no difference how the initial state was attained.就t1時刻的狀態(tài)而言，它與初始狀態(tài)是怎樣實現(xiàn)的無關。4 Thus the state at t0 constitutes a complete history of the syste

40、m behavior prior to t0, insofar as that history affects future behavior.因此，t0時刻的狀態(tài)構成了t0以前系統(tǒng)活動狀態(tài)的歷史，這個歷史狀態(tài)在一定范圍內(nèi)影響（系統(tǒng)）未來的行為。B 狀態(tài)方程1 In transfer function models these equations are transformed and variables are eliminated between them to find the relation between selected input and output variables.在傳

41、遞函數(shù)模型中，這些方程經(jīng)過（拉氏）變換，并消去中間變量，以求得選定的輸入輸出變量間的關系。2 The generalized coordinates and momenta of Hamiltonian and Lagrangian mechanics are, in fact, a set of state variables.事實上，哈密爾頓和拉格朗日力學的廣義坐標和動量就是一組狀態(tài)變量。A 可控性，可觀性和穩(wěn)定性1 Since complete state controllability does not necessarily mean complete control of the

42、output, and vice versa, complete output controllability is separately defined in the same manner.因為狀態(tài)完全能控性不一定意味著輸出的完全可控，而且反之亦然，所以輸出完全能控性以類似的方式單獨定義。2 Only local asymptotic stability with respect to the established equilibrium state can be guaranteed for linear analyses.只有相對于（系統(tǒng)）建立的平衡狀態(tài)的局域漸近穩(wěn)定才能保證線性分析

43、（可以應用）。B 最優(yōu)控制系統(tǒng)1 Complete controllabillity in the mathematical sense is a necessary but not sufficient condition for the existence of an optimal control.在數(shù)學意義上，完全能控是最優(yōu)控制存在的必要條件但非充分條件。2 mathematically that is. 數(shù)學上是如此的。3 With the exception of some linear plants, the variational approach of Pontryagins

44、 minimum principle leads to a nonlinear two-point boundary-value problem that must be solved by numerical methods.除去一些線性控制對象外，龐垂根最小原理的推論引出了一個必須用以數(shù)字表示的方法求解的問題。A 傳統(tǒng)控制與智能控制1 The term “conventional (or traditional) control” is used here to refer to the theories and methods that were developed in the pas

45、t decades to control dynamical systems, the behavior of which is primarily described by differential and difference equations.“傳統(tǒng)控制”這個術語是指在過去的幾十年里發(fā)展起來的用于控制以微分和差分方程表述的動態(tài)系統(tǒng)的理論和方法。2 Because intelligent control addresses more general control problems that also include the problems addressed by conventio

46、nal control, it is rather difficult to come up with meaningful bench mark examples.由于智能控制解決了包含傳統(tǒng)控制解決的問題在內(nèi)的更多更廣泛的問題，所以提出有代表性的例子相當困難。3 Note that the precise definition of “intelligence” has been eluding mankind for thousands of years.我們注意到“智能”的精確定義已經(jīng)數(shù)千年不為人類所知了。B 人工神經(jīng)網(wǎng)絡 1 The number of hidden neurons m

47、ust be determined so that the network performs its best, one of the methods used often is trial and error.必須確定隱含神經(jīng)元的數(shù)量以使網(wǎng)絡性能最優(yōu)，一種常用的方法是試湊法。2 Neural networks are performing successfully where other methods do not, recognizing and matching complicated, vague, or incomplete patterns.神經(jīng)網(wǎng)絡在識別匹配復雜、含糊和不完整圖

48、案的問題上得到了成功的應用，而其他方法對此問題無能為力。PART 3 計算機控制技術 A 計算機的結構與功能1 how the instruction execution cycle is broken down into its various components.指令執(zhí)行周期怎樣分解成不同的部分。2 One way to achieve meaningful patterns is to divide up the bits into fields一種得到（指令）有效形式的方法是將（這些）位分成段3 The majority of computer tasks involve the A

49、LU, but a great amount of data movement is required in order to make use of the ALU instructions. 計算機的大多數(shù)工作涉及到ALU(邏輯運算單元)，但為了使用ALU指令，需要傳送大量的數(shù)據(jù)。B 計算機與網(wǎng)絡基礎1 Some INPUT DEVICES allow direct human/machine communication, while some first require data to be recorded on an input medium such as a magnetizab

50、le material.有些輸入設備允許直接的人機對話，而有些輸入設備則需要先將數(shù)據(jù)存儲在諸如磁性材料等輸入介質上。2 connected directly to (or ONLINE to) a computer online與“直接連接”的概念不同，前者是“聯(lián)機”，此處是指工作站鍵盤與主機連在一起工作，后者是指“物理連接”。3 Similarly, at a local level within, say, a single building句中的say是“比如說”的意思。A 外部信號與設備的接口1 In this interface, there is a “tristate” buff

51、er which when it is enabled will force the processor bus to have the same binary value as the external data lines.在這種接口中，有一個三態(tài)緩沖器，它能迫使處理器總線與外部數(shù)據(jù)線有相同的二進制值。2 Ui is then removed and a known negative constant reference voltage U is integrated which produces a ramp down.然后去掉Ui，對一個已知的負常數(shù)參考電壓U積分以產(chǎn)生一個下降的斜坡。

52、B 計算機的應用1 Computer simulation as a powerful analytic tool widely used in scientific research and engineering design demonstrates unrivalled advantages.作為一種廣泛應用于科學研究和工程設計的有力分析工具，計算機仿真顯示出無與倫比的優(yōu)點。2 Data, diagrams, tables, etc. showing its shape, dimension, structure, fabrication and the material it is

53、made from are input as the software requires.表示產(chǎn)品形狀、尺寸、結構、組成和制造材料的數(shù)據(jù)、圖形和表格等將按軟件的需求輸入。3 The solution to that problem was then based on asynchronous low-speed lines organized in either a star topology with a line dedicated to each terminal, or a tree topology with multidrop lines.此問題的解決基于異步低速的傳輸線，其結構可

54、以是每臺終端單配一線的星狀拓撲結構，也可以是多分支線的樹狀拓撲結構。 A PLC概述 1 One can also implement a gateway by means of an OPC DX server, a SCADA application or a specific communication card such as the APPLICOM one.句中的OPC DX即OLE for Process Control Data Exchange. OLE (Object Linking and Embedding) 為對象的鏈接與嵌入，SCADA（Supervisory Co

55、ntrol And Data Acquisition）為數(shù)據(jù)采集與監(jiān)視控制系統(tǒng)。B PAC新一代工業(yè)控制系統(tǒng), 可編程自動化控制的未來1 So the “twenty percenters” either lived without functionality not easily accomplished with a PLC or cobbled together a system that included a PLC for the control portion of the code and a PC for the more advanced functionality. 因此那

56、些要開發(fā)“20%應用”的工程師們要么使用一個PLC，無法輕松實現(xiàn)系統(tǒng)所需的功能，要么采用既包含PLC又包含PC的混合系統(tǒng)，他們利用PLC來執(zhí)行代碼的控制部分，用PC來實現(xiàn)更高級的功能。2 Multi-domain functionality, At least 2 of logic, motion, PID control, drives, and process on a single platform.多功能性，在一個平臺上有邏輯、運動、PID控制、驅動和處理中的至少兩種以上功能。3 Single multi-discipline development platform incorpor

57、ating common tagging and a single database for access to all parameters and functions.單一的多規(guī)程開發(fā)平臺使用通用標簽和單一的數(shù)據(jù)庫來訪問所有的參數(shù)和功能。4 These RTOSs provide the capability to control all aspects of the control system, from the I/O read and write rates to the priority of individual threads spawned on the controlle

58、r. 這些RTOS能控制系統(tǒng)的各個層面，從I/O讀寫速率到控制器上各個線程的優(yōu)先級。A 單片機基礎1 The single-chip microcomputer is the culmination of both the development of the digital computer and the integrated circuit, arguably the two most significant inventions of the 20th century.單片機是數(shù)字計算機和集成電路發(fā)展中的一個頂峰，而這二者可以說是20世紀的兩項最有意義的發(fā)明。2 on-chip ROM

59、 譯為“片內(nèi)ROM”。B 了解數(shù)字信號處理器和它的用途1 Today, there is in fact a blurring between the roles of microprocessor and digital signal processor.當前，微處理器和數(shù)字信號處理器兩者的任務界限已經(jīng)變得模糊了。2 We are now in the world of computing and software where manipulation of binary numbers is bread and butter stuff.我們現(xiàn)在生活在計算機和軟件的世界中，在這個世界中，二

60、進制數(shù)字的處理就好比是面包和黃油，不可缺少。3 The exacting tolerances demanded of filters in speech processing systems simply could not be maintained over time with analog techniques, subject as they are to temperature drift, component tolerances, and aging.在語音處理系統(tǒng)里使用模擬技術，濾波器對誤差的苛刻要求就得不到保證，這主要由于模擬技術存在溫度漂移、元件誤差和老化等問題。4 In