专通信工程业英语小抄总汇.doc

基本函数式(1) a-b=(a+b)(a-b) a squared minus b squared equals openparenthesis a plus b close parenthesis times open parenthesis a minus b closeparenthesis.(2) X plus one over the quantity x squared times the quantity x cubed minus fourto the two-third power.(3) The limit as n approaches infinity of thequantity one over n squared times one plus two plus to plus n.(4) One half open brace, a open bracket bplus open parenthesis c minus d close parenthesis close bracket close brace.(5) Capital sigma the quantity a sub n timesb sub n times the cosine of n time omegaover 2 times pi from n equals one to n equals five.(6) Product of all a from n equals one toInfinity.(7) max(a,a,a) ,min(a,a,a) Maximum/minimum value of the seriesa 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/x y prime equals minus one over x to thenth power. The first derivative of y with respect tox equals minus one over x to nth power.(11) The second derivative of y with respectto x equals a squared times e to the powerof minus a times x.(12) The indefinite integral of the quantity aover x minus a with respect to x equals atimes the quantity logarithm of the absolute value of 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) f(x)=1+ln (x-2) The function of x equals one plus log the quantity x minus 2 to the base e.(16) sin3x3sinx-4sinx The sine of three x is equivalent to three times sine of x minus four times the quantity sine x cubed.句子翻译1 The concepts of signals and system arise in a wide variety of fields, and the ideas and techniques associated with these concepts play an important role in such diverse areas of science and technology as communications, aeronautics and astronautics, circuit design, acoustics, seismology, biomedical 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、声学、地震学、生物学、生物医学工程、发电和输电系统、化学过程控制和语音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。2 Without some restrictions, when the characterization of a system requires a complete input-out-put relationship, knowing the output of a system to a certain set of input doe not allow us to determine the output of the system to other sets of inputs.当系统的特性描述要求完整的输入输出关系时，如果没有约束条件，即使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。3 An example of a finite-energy signal is a signal that takes on the value 1 for 0t1 and 0 otherwise.举一个有限能量信号的例子：信号在0t1，而在其他时间范围取值为0。4 This, of course, makes sense, since if there is a nonzero average energy per unit time, then integrating or summing this over an infinite time 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。5 We can bring continuous-time and discrete-time systems together through 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将连续时间和离散时间系统放在一起考虑。我们可以将一些离散时间系统的概念推广，用以处理抽样后的连续时间系统。6 One of the most important motivations for the development of general tools for analyzing and designing systems is that systems from many different applications have very similar mathematical descriptions.许多具有不同应用的系统都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。1 In most cases, these signals originate as sensory data from the real world: seismic vibrations visual images, 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。2 Fouriers representation of functions as a superposition 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。3 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.如果f（t）是非周期信号，那么用周期函数例如正弦与余弦的和，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，但是这要求在端点处附加连续性。4 If the 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，就有必有对输入信号加窗，这样信号在端点处就会收敛于零。5 A digital filter is a mathematical algorithm implemented in hardware, firmware, and/or software that operates on a digital input signal 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。6 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.用傅里叶级数设计FIR滤波器的基本思想是计算出此滤波的单位冲激响应来逼近所期望的滤波器的频率响应。词汇翻译Electronics 电子学，电子工业Battery 电池LSI Large Scale Integration 大规模集成电路ultraviolet紫外的，紫外线的radiation 辐射LED light-emitting diodes 发光二级管capacitor 电容，电容器integrated circuit 集成电路wireless telegraphy无线电报passive devices 无源器件电流electricity二极管diode半导体semiconductor真空管vacuum tube有源器件active device无线电报wireless telegraphy印刷电路 printed circuit高清晰电视high-definition television HDTV电阻器 resistorampere 安培conductivity 传导性，传导率magnetic core磁芯insulator 绝缘体，绝热器dielectric 电介质，绝缘体Thevenins Theorem 戴维南定理Negative terminal负端,负极接线柱inductance 感应系数，自感应polarity 极性电荷 charge电感reactance节点node电容器condenser绝缘体 insulator等效电阻equivalent resistance叠加定理Superposition Theoremsemiconductor 半导体number system 计数制IC 集成电路Commutative Law 交换律AC 交流DC 直流Distribution Law 分配率binary具有两个的;二进制的; 二变量的inverter变换器; 倒相器, 倒换器; 反演器; 逆变器，“非”门negative否定的, 否认的，反面的, 消极的反对的，负的，阴极的Sequential 时序的双极管bipolar transistorN沟道N-Channel晶体管transistor线性化linearization布尔代数Boolean algebra真值表truth table触发器Flip-Flop 组合逻辑电路combinational logic circuit相邻项adjacent积和式Sum-Of-Productssignal and system信号与系统aeronautics and astronautics航空学和太空航空学continuous-time signals连续时间信号signal energy and power信号的能量与力量total energy总能量complex number复数infinite time interval无限时间间隔average power平均功率physical system因果系统automotive vehicle 汽车信号处理Signal processing电路设计Circuit design离散时间信号Discrete time signal非零常数Nonzero constant独立变量independent variable瞬时功率instantaneous power平均能量average energy无限能量infinite energy互相作用的子系统Subsystems interact图像增强image enhancementDSP Digital Signal Processing 数字信号处理symmetry properties对称性time domain时域frequency domain频域chop up 切开，割断weight function权值函数uniformly space 均一的空间sparse matrices稀疏矩阵fast Fourier transform快速傅里叶变换Fourier series傅里叶级数线性相位Linear phase偶函数even function传递函数transfer function吉伯斯现象Gibbs phenomenon通带Pass band阻带stop-band主瓣mainlobe旁瓣sidelobe非时变有限脉冲滤波器non-time-variable limited pulse filter非递归的non-recursiveMessage Switching报文交换Electrical Communication电子通信ARPANET阿帕网International Network Working Group互联网Packet Switch分组交换Wireless无线的Telnet远程通信网instant transmission及时传输storage存储transmission传送光速Speed of light长距离及时传输The long distance instant transmission调频frequency modulation调幅amplitude modulation同步synchronized接口信息处理机interface message processors原理principleUWB超宽带General Packet Radio Service通用无线分组业务wireless personal area networks无限个人区域网络adapter适配器ad hoc network 自组网carrier sense multiple access载波监听多路访问OFDM Orthogonal Frequency Division Multiplexing正交频分复用技术Wireless Local Area Networks无限地区区域网络encryption编密码radio frequency identification射频识别个人通信服务PCS Personal communications Services蜂窝数字分组数据CDPD Cellular Digital Packet Data无线电传输技术Radio transmission technology时分复用TDM time-division multiplexing码分复用CDM code division multiplexing物理层Physical level服务质量QoS Quality of Service接口interface密码cipher code说明书Instructions图像解释题图2-1 Any source of voltage, including batteries, has two points for electrical contact. We can provide such a path for the battery by connecting a piece of wire from one end of the battery to the other. Forming a circuit with a loop of wire, we will initiate a continuous flow of electrons in a clockwise direction, which is shown in Fig.2-1. So long as the battery continues to produce voltage and the continuity of the electrical path isnt broken, electrons will continue to flow in the circuit. Following the metaphor of water moving through a pipe, this continuous, uniform flow of electrons through the circuit is called a current. So long as the voltage source keeps “pushing” in the same direction, the electron flow will continue to move in the same direction in the circuit. This single-direction flow of electrons is called a Direct Current, or DC. electron circuits are explored where the direction of current switches back and forth: Alternating Current, or AC. But for now, well just concern ourselves with DC circuits.图2-2 We see that I is the only current flowing into the node. However, there are three paths for current to leave the node, and these current are represented by I , I and I . Once charge has entered into the node, it has no place to go except to leave （this is known as conservation of charge）. The total charge flowing into a node must be the same as the total charge flowing out of the node. So IB+IC+ID=IA Bringing everything to the left side of the above equation, we get (IB+IC+ID)-IA=0Then, the sum of all the currents is zero. This can be generalized as follows Ii=0Note the convention we have chosen here: current flowing into the node is taken to be negative, and currents flowing out of the node are positive. 图2-12The PNP transistor is the king of the traditional bipolar analog integrated circuits world. In fact in the most basic and most cost effective analog IC process, the chip designer has at its disposal just that; a good NPN transistor. The rest, PNPs, resistors and capacitors are just by-products , a notch better than parasites. For intuitive, back-of-the-envelope type analysis, it is sufficient to model the transistor mostly in DC (Direct Current), keeping in mind that the bandwidth of such an element is finite.When complexity, like small-signal AC (Alternate Current) behavior, is added to the model, computing simulations should be used since the math quickly becomes hopeless. In Fig.2-12 the NPN transistor is shown with its symbol and its DC model. In this component the current flow enters the collector and base and exits the emitter. Simply stated, the transistor conducts a collector current IC which is a copy of the base current IB amplified by a factor of beta . It follows that the emitter current IE is one plus beta times the base current. A typical value for the amplification factor is 100. NPNs have excellent dynamic performance, or bandwidth, measured by their cutoff frequency; easily above 1GHz.图2-13 The PNP transistor is complementary to the NPN, with the current flow entering the emitter and exiting the collector and base, the opposite of what happens in the NPN, which is shown in Fig.2-13. Simplicity dictates that PNPs are a by-product of the NPN construction, hence they often have less beta current gain and are slower than NPNs. A typical value for their amplification factor is 50 their cutoff frequency (fT), is generally above 1 MHz.图2-14 The dual of Bipolar NPN and PNP transistors in CMOS technology are the P-Channel MOS transistors in Fig.2-14. The general function of the transistors is the same independently as their implementation but there are pros and cons to using both technologies. Generally speaking, the base, the emitter, and the collector of the bipolar transistor are analogous to the gate, source and drain of the MOS transistor, respectively. The bipolar transistors main problem, which is not present in CMOS, is their need for a base current in order to function. Such current is a net transfer loss from emitter to collector. While the base current is small in small signal operation, in power applications, where the transistor is used as a switch, the base current necessary to keep the transistor on can be very high.图2-15 2-16 2-17 AND gateproduces a 1 output id both of its inputs are 1.The logic expression is F=AB. OR gateproduces a 1 output if one or both of its inputs are 1, produces a 0 output only if both of its inputs are 0.The logic expression is F=A+B. NOR gatemore commonly called an inverter, produces an output value that is the opposite of the input value. The logic expression is F=A. Three common symbols for every gate are shown in Fig.2-15到2-17 that we can meet in all kinds of references.图2-18 The basic electronic digital operations are also NOT, AND, OR, but there are combinations of these that also commonly used: the NAND, NOR and EXCLUSIVE NOR. This is an example of convenient packaging of NAND and AND gates in integrated circuit form in Fig.图2-19“Flip-flop” is the common name given to two-state devices which offer basic memory for sequential lo