电子信息与通信工程专业外语期末考试重点

1、LSI large-scale integration大规模集成电路PLC Programmable Logic Controller可编程逻辑控制器LED light-emitting diodes发光二极管IC Integrated circuit 集成电路AC Alternate Current交流DC Direct Current直流DSP digital signal processing数字信号处理digital signal processor数字信号处理器NFC Near Field Communication近距离无线通信PCS Personal Communications

2、 Service个人通信服务PDA Personal Digital Assistance掌上电脑（个人数字助理）PDC Personal Data Cellular分组数据蜂窝QoS Quality of Service 服务质量RTT Radiation Tracking Transducer无线电传输技术UWB Ultra Wide Band超宽带二、翻译公式基本函数公式英语-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均为正整数)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-英语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年之前就发现了热电效应，电解效应，和光电效应。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”爱迪生发现，在微弱的电流从加热的灯丝流向真空管内附着的金属板，这可就是众所周知的爱迪生效应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.采用真空管使得信号的控制成为可能，这是早期的电报电话不能实现的，也是早期用高压电火花产生无线电波的发射机所不能实现的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频信号，并将这些信号叠

17、加在无线电波上。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 .晶体管的功能与真空管相似，但尺寸小，重量轻，功耗低，工作更为可靠，它由金属电极和半导体材料构成，成本较低。l Improvements in integrated circuits and microprocessors have enhanced the fun

18、ctionality of Programmable Logic Controllers.集成电路和微处理器的改进增强了可编程逻辑控制器的功能。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只要电池持续供电，并且导线没有断开，电子将始终在回路中流动。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.当电容与电池相连，电子将从电池的负极流出，病聚集在电容与该端相联的极板上，称电容被充电l Whenver electrons flow through a conductor ,a magnetic field will develop around that

20、conductor/只要电子束流过导体，就将在这个导体周围产生磁场。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，玻璃在室温下是一个非常好的绝缘体，但当它加热到相当高的温度时它就变成一个导体。l Whenever an electric voltage exists between two separated conductors,an electric field is pr

21、esent within the space between those conductor.只要在两个独立的半导体间存在电压，则他们之间将会产生一个磁场。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.通常导体里的自由电子式随机运动的，没有确定的

22、方向或速度，但是电子受力后可沿相同方向通过导体。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.信号与系统的概念出现在广阔的范围内，在科学技术的不同领域，如通信、航空航天、电路设计、升学、地震学、生物医学工程、发电和输电系统、化学过程控制和语言处理中都离不开这个概念的思想与技术。它在科学技术中发挥了重要作用。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.当系统的特征性描述要求完整的输入输出关系时，如果没有约束条件，及时知道了系统对某些特定输入产生的输出时，我们也并不知道系统对其他输入产生的输出。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.举一个有限能量信号的例子：信号在0=t=1内其值为去，而其他时间范围取值为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.当然这是有意义的，因为如果单位时间内存在一个非零的平均能量，那么在一

26、个无限的时间间隔范围内，对其积分或者求和就会产生一个无限的能量总和。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.我们可以在抽样的概念下进行连续时间和离散时间系统放在一起考虑。我们可以将一些离

27、散时间系统的概念推广，用以处理抽样后的连续时间系统。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.许多具有不同应用的程序搜有相类似的数学描述，这是开发系统分析和设计通用工具软件的最重要的动机之一。l Ele

28、ctronic amplifiers are often symbolized by a simple triangle shape,where the internal components are not individually represented.电子放大器一般都表示成三角形形状，内部器件并不分别表示出来。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.增大同相输入端的电压，会使输出电压增大；增大反向输入端的电压，会使输出电压减小。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.因为我们知道，运算放大器的两个输入端之间有无穷大的电阻，所以我们完全可以假设他们

30、没有增加或分担任何电流。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.换句话说，我们可以认为R1和R2串联，即通过R1的电流一定会通过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.在大多数情况下，这些信号来源于人对真实世界的感觉，比如地震的震动，视觉图像，声音波形等。数字信号处理是一种数学工具，是一种用来处理那些将上述信号转换成数字形式后的信号的算法和技术。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.函数的傅里叶表示，即将函数表示成正弦和余弦信号的叠加，这种方法已经广泛用于微分方程的解析法和数值法求解过程以及通信信号的分析和处理。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)是非周期信号，那么用周期函数例如正弦和余弦的和，并不能精确地表示该信号f(t)。你可以人为的拓展这个信号使其具有周期性，但这要求在端点处附加连续性。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.如果信号有急剧的过渡，就有必要对输入信号加窗，这样信号在端点出就会收敛于零。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.数字滤波器是一种数学算法，它可以用硬件、固件以及软件来实现。它作用于数字输入信号产生数字输出信号从而达到滤波目标。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.用傅里叶

36、级数设计FIR滤波器的基本思想是计算出此滤波器的单位冲激响应来逼近所期望的滤波器的频率响应。翻译：函数的傅里叶表示，即将函数表示成正弦和余弦信号的叠加，这种方法已经广泛用于微分方程的解析法和数值法求解过程以及通信信号的分析和处理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. 傅里叶变换的效用在于它能够在时域范围内分析它的频率内容。变换的第一步是将时域上的函数转换为时域表示。然后就可以分析信号的频率内容了。因为变换函数的傅里叶系数代表各个正弦和余弦函数在各自对应频率区间的分配。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.傅里叶逆变换就会按你刚才设想的那样将频域数据转换为时域的.An inverse Fourier transform does just what youd expect,transform data form the frequency domain into the time domain.离散型傅里叶变换是通过他有限的采样点来评

39、估函数的傅里叶变换。采样点代表了其他时间的信号。ThediscreteFouriertransform(DFT)estimatestheFouriertransformofafunctionfromafinitenumberofitssampledpoints.Thesampledpointsaresupposedtobetypicalofwhatthesignallookslikeatallothertimes.离散型傅里叶变换具有和连续型傅里叶变换几乎完全相同的对称特性。此外，通过离散型傅里叶变换的公式，我们可以轻易推出离散型傅里叶变换的公式。因为这两个公式几乎完全相同。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)是非周期信号，那么用周期函数例如正弦和余弦的和，并不能精确的表

41、示该信号f(t)。你可以人为的拓展这个信号使其具有周期性，但是这要求在端点处附加连续性。窗口傅里叶变换能够更好的解决关于非周期信号的表示问题。窗口傅里叶变换同样适用于时域和频域上信号信息的提供。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