電子信息與通信工程專業(yè)外語期末考試重點(diǎn)

1、LSI large-scale integration大規(guī)模集成電路PLC Programmable Logic Controller可編程邏輯控制器LED light-emitting diodes發(fā)光二極管IC Integrated circuit 集成電路AC Alternate Current交流DC Direct Current直流DSP digital signal processing數(shù)字信號處理digital signal processor數(shù)字信號處理器NFC Near Field Communication近距離無線通信PCS Personal Communications

2、 Service個(gè)人通信服務(wù)PDA Personal Digital Assistance掌上電腦（個(gè)人數(shù)字助理）PDC Personal Data Cellular分組數(shù)據(jù)蜂窩QoS Quality of Service 服務(wù)質(zhì)量RTT Radiation Tracking Transducer無線電傳輸技術(shù)UWB Ultra Wide Band超寬帶二、翻譯公式基本函數(shù)公式英語-公式1. a2-b2=(a+b)(a-b)a squared minus b squared equals open parenthesis a plus b close parenthesis times ope

3、n parenthesis a minus b close parenthesis.2.x plus one over the quantity x squared times the quantity x cubed minus four to the two-third power.3.The limit as n approaches infinity of the quantity one over n squared times one plus two plus to plus n.4. ab+(c-d)one half open brace , a open bracket b

4、plus open parenthesis c minus d close parenthesis close bracket close brace.5.Capital sigma the quantity a sub n times b sub n times the cosine of n time omega over 2 times pi from n equals one to n equals five.6.Product of all an from n equals one to infinity.7. max (a1,a2,an),min (a1,a2,an)Maximum

5、/minimum value of the series a sub one to a sub n.8.Limit as n approaches infinity of the quantity of one plus one over n to the nth power equals e.9. Upper/lower limit of a sub n as n approaches/tends to infinity.10. y=-1/xny prime equals minus one over x to the nth power.The first derivative of y

6、with respect to x equals minus one over x to nth power.11.The second derivative of y with respect to x equals a squared times e to the power of minus a times x.12.The indefinite integral of the quantity a over x minus a with respect to x equals a times the quantity logarithm of the absolute value of

7、 x minus a plus c.13.The integral from 0 to pi over two of the quantity one over one plus a times cosine of x with respect to x.14. (a0,m,n均為正整數(shù))a to the minus m over n power equals one over the nth root of a to the mth power, where a is greater than zero, and both m and n are positive numbers.15.Th

8、e function of x equals one plus log the quantity x minus 2 to the base e.16.The sine of three x is equivalent to three times sine of x minus four times the quantity sine x cubed.公式-英語3-22 H as the function of equals capital sigma h as the function of n times e to the power of minus j times times n f

9、rom n equals minus infinity to n equals infinity.3-23 -nh as the function of n equals one over two times pi times the integral from minus pi to pi of the quantity of H as the function w times e to the power of j times w times n with respect to w, where n is greater than or equal minus infinity and n

10、 is less than or equal infinity3-24 m h as the function of n equals one over pi times the integral from zero to pi of H as the function of times the cosine of times n with respect to ,where n is greater than or equal zero.3-25 h(-n)=h(n) n0 h as the function of minus n equals h as the function of n,

11、where n is greater than or equal zero3-26 H prime as the function of n equals h as the function of n where n is greater than or equal minus M and n is less than or equal M,otherwise h prime as the function of n equals zero3-27 H prime as the function of Z equals the capital sigma the quantity of h p

12、rime as the function of n times z to the minus nth power from n equals minus M to equals M.4-1 The integral along the closed-path line C of vector H,equals the surface integral of the sum of the vector J plus the time derivative vector D4-2 4-3 The integral along the closed-path line C of vector H e

13、quals minus the surface integral of the time derivative of vector B4-4 The integral through the closed surface of vector B equals zero4-5 The integral through the closed surface of vector D equals the integral enclosed with the surface of charge4-6 The integral along the closed-path line c of vector

14、 A equals the surface integral of curl of vector A.4-7 The integral through the closed surface of vector A equals the volume integral of the divergence of vector A.NOTEl Thermoelectricity,electrolysis,and the photovoltaic effect were all discovered before 1840.在1840年之前就發(fā)現(xiàn)了熱電效應(yīng)，電解效應(yīng)，和光電效應(yīng)。l Edison fo

15、und that a small current passed from the heated lamp filament to a metal plate mounted inside the vacuum envelop .Today this is known as the “Edison effect”愛迪生發(fā)現(xiàn)，在微弱的電流從加熱的燈絲流向真空管內(nèi)附著的金屬板，這可就是眾所周知的愛迪生效應(yīng)l With vacuum tubes the manipulation of signals became possible ,which colud not be done with the e

16、arly telegraph and telephone circuit or with the early transmitter using high-voltage sparks to create radio waves.采用真空管使得信號的控制成為可能，這是早期的電報(bào)電話不能實(shí)現(xiàn)的，也是早期用高壓電火花產(chǎn)生無線電波的發(fā)射機(jī)所不能實(shí)現(xiàn)的l Vacuum tubes strengthened weak audio signals and allowed these signals to be superimposed on radio weave.真空管放大微弱的音頻信號，并將這些信號疊

17、加在無線電波上。l The transistor function like the vacuum tube,but it is tiny by comparison,weighs less,consumes less power is much more reliable,and is cheaper to manufactor .晶體管的功能與真空管相似，但尺寸小，重量輕，功耗低，工作更為可靠，它由金屬電極和半導(dǎo)體材料構(gòu)成，成本較低。l Improvements in integrated circuits and microprocessors have enhanced the fun

18、ctionality of Programmable Logic Controllers.集成電路和微處理器的改進(jìn)增強(qiáng)了可編程邏輯控制器的功能。l So long as the battery continues to produce voltage and the continuity of the electrical path isntbroken ,electrons will continue to fiow in the circuit只要電池持續(xù)供電，并且導(dǎo)線沒有斷開，電子將始終在回路中流動。l If a condenser is connected to a battery,t

19、he electrons will flow out of the negative terminal of the battery and accumulate on the conductor plate connected to that side.Thus the condenser is said to be chargrd.當(dāng)電容與電池相連，電子將從電池的負(fù)極流出，病聚集在電容與該端相聯(lián)的極板上，稱電容被充電l Whenver electrons flow through a conductor ,a magnetic field will develop around that

20、conductor/只要電子束流過導(dǎo)體，就將在這個(gè)導(dǎo)體周圍產(chǎn)生磁場。l Glass,for instance ,is a very good insulator at room temperature,but becomes a conductor when heated to a very high temperature.例如，玻璃在室溫下是一個(gè)非常好的絕緣體，但當(dāng)它加熱到相當(dāng)高的溫度時(shí)它就變成一個(gè)導(dǎo)體。l Whenever an electric voltage exists between two separated conductors,an electric field is pr

21、esent within the space between those conductor.只要在兩個(gè)獨(dú)立的半導(dǎo)體間存在電壓，則他們之間將會產(chǎn)生一個(gè)磁場。l While the normal motion of “free” electrons in a conductor is random,with no particular direction or speed,electrons can be influenced to move in a coordinated fashion through a conductive material.通常導(dǎo)體里的自由電子式隨機(jī)運(yùn)動的，沒有確定的

22、方向或速度，但是電子受力后可沿相同方向通過導(dǎo)體。l The concept of signals arise in a wide variety of field, and the ideas and techniques associated with these concepts play an important in such diverse areas of science and technology as communications, aeronautics and astronautics, circuit design, acoustics, seismology, bio

23、medical engineering, energy generation and distribution systems, chemical process control, and speech processing.信號與系統(tǒng)的概念出現(xiàn)在廣闊的范圍內(nèi)，在科學(xué)技術(shù)的不同領(lǐng)域，如通信、航空航天、電路設(shè)計(jì)、升學(xué)、地震學(xué)、生物醫(yī)學(xué)工程、發(fā)電和輸電系統(tǒng)、化學(xué)過程控制和語言處理中都離不開這個(gè)概念的思想與技術(shù)。它在科學(xué)技術(shù)中發(fā)揮了重要作用。l Without some restrictions, when the characterization of a system requires a co

24、mplete input-output relationship, knowing the output of a system to a certain set of input does not allow us to determine the output of the system to other sets of input.當(dāng)系統(tǒng)的特征性描述要求完整的輸入輸出關(guān)系時(shí)，如果沒有約束條件，及時(shí)知道了系統(tǒng)對某些特定輸入產(chǎn)生的輸出時(shí)，我們也并不知道系統(tǒng)對其他輸入產(chǎn)生的輸出。l An example of a finite-energy signal is a signal that ta

25、kes on the value 1 for 0=t=1 and 0 otherwise.舉一個(gè)有限能量信號的例子：信號在0=t=1內(nèi)其值為去，而其他時(shí)間范圍取值為0。l This, of course, makes sense, since if there is a nonzero average per unit time, then integrating or summing this over an infinite the interval yields an infinite amount of energy.當(dāng)然這是有意義的，因?yàn)槿绻麊挝粫r(shí)間內(nèi)存在一個(gè)非零的平均能量，那么在一

26、個(gè)無限的時(shí)間間隔范圍內(nèi)，對其積分或者求和就會產(chǎn)生一個(gè)無限的能量總和。l We can bring continuous-time and discrete-time systems together though the concept of sampling, and we can develop some insights into the use of discrete-time systems to process continuous-time signals that have been sampled.我們可以在抽樣的概念下進(jìn)行連續(xù)時(shí)間和離散時(shí)間系統(tǒng)放在一起考慮。我們可以將一些離

27、散時(shí)間系統(tǒng)的概念推廣，用以處理抽樣后的連續(xù)時(shí)間系統(tǒng)。l One of the most important motivations for the development of general tools for analyzing and designing systems is the system is that systems from many different applications have very similar mathematical descriptions.許多具有不同應(yīng)用的程序搜有相類似的數(shù)學(xué)描述，這是開發(fā)系統(tǒng)分析和設(shè)計(jì)通用工具軟件的最重要的動機(jī)之一。l Ele

28、ctronic amplifiers are often symbolized by a simple triangle shape,where the internal components are not individually represented.電子放大器一般都表示成三角形形狀，內(nèi)部器件并不分別表示出來。l An increasingly positive voltage on the (+) input tends to drive the output voltage more positive ,and an increasingly positive voltage on

29、 the (-) input tends to drive the output voltage more negative.增大同相輸入端的電壓，會使輸出電壓增大；增大反向輸入端的電壓，會使輸出電壓減小。l Because we know that both input of the op-amp have extremely high impedance,we can safely assume they wont add or subtract any current through the divider.因?yàn)槲覀冎?，運(yùn)算放大器的兩個(gè)輸入端之間有無窮大的電阻，所以我們完全可以假設(shè)他們

30、沒有增加或分擔(dān)任何電流。l In the other words, we can treat R1 and R2 as being in series with each other;all of the electrons flowing through R1 must flow through R2.換句話說，我們可以認(rèn)為R1和R2串聯(lián)，即通過R1的電流一定會通過R2.l In most cases, these signals originate as sensory data from the real world: seismic vibrations, visual images,

31、 sound waves, etc. DSP is the mathematics, the algorithms, and the techniques used to manipulate these signals after they have been converted into a digital form.在大多數(shù)情況下，這些信號來源于人對真實(shí)世界的感覺，比如地震的震動，視覺圖像，聲音波形等。數(shù)字信號處理是一種數(shù)學(xué)工具，是一種用來處理那些將上述信號轉(zhuǎn)換成數(shù)字形式后的信號的算法和技術(shù)。l Fouriers representation of functions as a supe

32、rposition of sines and cosines has become ubiquitous for both the analytic and numerical solution of differential equations and for the analysis and treatment of communication signals.函數(shù)的傅里葉表示，即將函數(shù)表示成正弦和余弦信號的疊加，這種方法已經(jīng)廣泛用于微分方程的解析法和數(shù)值法求解過程以及通信信號的分析和處理。l If f(t) is a nonperiodic signal, the summation o

33、f the periodic funtions, such as sine and cosine, does not accurately represent the signal. You could artificially extend the signal to make it periodic but it would require additional continuity at the endpoints.如果f(t)是非周期信號，那么用周期函數(shù)例如正弦和余弦的和，并不能精確地表示該信號f(t)。你可以人為的拓展這個(gè)信號使其具有周期性，但這要求在端點(diǎn)處附加連續(xù)性。l If th

34、e signal has sharp transitions, it is necessary to window the input data, so that the sections converge to zero at the endpoints.如果信號有急劇的過渡，就有必要對輸入信號加窗，這樣信號在端點(diǎn)出就會收斂于零。l A digital filter is a mathematical algorithm implemented in hardware, firmware, and/or software that operates on a digital input si

35、gnal to produce a digital output signal for achieving filtering objectives.數(shù)字濾波器是一種數(shù)學(xué)算法，它可以用硬件、固件以及軟件來實(shí)現(xiàn)。它作用于數(shù)字輸入信號產(chǎn)生數(shù)字輸出信號從而達(dá)到濾波目標(biāo)。l The basic idea of Fourier series method is to design an FIR filter that approximates the desired frequency response of filter by calculating its impulse response.用傅里葉

36、級數(shù)設(shè)計(jì)FIR濾波器的基本思想是計(jì)算出此濾波器的單位沖激響應(yīng)來逼近所期望的濾波器的頻率響應(yīng)。翻譯：函數(shù)的傅里葉表示，即將函數(shù)表示成正弦和余弦信號的疊加，這種方法已經(jīng)廣泛用于微分方程的解析法和數(shù)值法求解過程以及通信信號的分析和處理Fouriers reprentation of function as a superposition of sines and consines has become ubiquitous for both the analytic and numerical solution of differential equations and for analysis a

37、ndd treatment of c ommunication signals. 傅里葉變換的效用在于它能夠在時(shí)域范圍內(nèi)分析它的頻率內(nèi)容。變換的第一步是將時(shí)域上的函數(shù)轉(zhuǎn)換為時(shí)域表示。然后就可以分析信號的頻率內(nèi)容了。因?yàn)樽儞Q函數(shù)的傅里葉系數(shù)代表各個(gè)正弦和余弦函數(shù)在各自對應(yīng)頻率區(qū)間的分配。Thetransformworksbyfirsttranslatingafunctioninthetimedomainintoafunctioninthefrequencydomain.The signal can then be analyzed for its frequency content becaus

38、e the Fourier coefficients of the transformed function represent the contribution of each sine and cosine function at each frequency.傅里葉逆變換就會按你剛才設(shè)想的那樣將頻域數(shù)據(jù)轉(zhuǎn)換為時(shí)域的.An inverse Fourier transform does just what youd expect,transform data form the frequency domain into the time domain.離散型傅里葉變換是通過他有限的采樣點(diǎn)來評

39、估函數(shù)的傅里葉變換。采樣點(diǎn)代表了其他時(shí)間的信號。ThediscreteFouriertransform(DFT)estimatestheFouriertransformofafunctionfromafinitenumberofitssampledpoints.Thesampledpointsaresupposedtobetypicalofwhatthesignallookslikeatallothertimes.離散型傅里葉變換具有和連續(xù)型傅里葉變換幾乎完全相同的對稱特性。此外，通過離散型傅里葉變換的公式，我們可以輕易推出離散型傅里葉變換的公式。因?yàn)檫@兩個(gè)公式幾乎完全相同。The DFT h

40、as symmetry properties almost exactly the same as the continuous Fourier transform. In addition, the formula for the inverse discrete Fourier transform is easily calculated using the one for the discrete Fourier transform become the two formulas almost identical.如果f(t)是非周期信號，那么用周期函數(shù)例如正弦和余弦的和，并不能精確的表

41、示該信號f(t)。你可以人為的拓展這個(gè)信號使其具有周期性，但是這要求在端點(diǎn)處附加連續(xù)性。窗口傅里葉變換能夠更好的解決關(guān)于非周期信號的表示問題。窗口傅里葉變換同樣適用于時(shí)域和頻域上信號信息的提供。If f(t) is a nonperiodic signal, the summation of the periodic functions (such as sine and cosine) does not accurately represent the signal. You could artificially extend the signal to make it periodic but it would require additional continuity at the endpoints. The windowed Fourier transform (WFT) is one solution to the problem of better representing the nonperiodic signal. The WFT can be used to give information about signals simultaneously in the time domain and in frequency