专业英语资料

英译中
1 More generally, signal processing is an operation designed for extracting, storing, and transmitting useful information. The distinction between useful and unwanted information is often subjective as well as objective.更普遍的是，信号处理，提取，存储和传输有用的信息而设计的操作。

有用和无用信息之间的区别往往是主观和客观。

2 DSP is the mathematics, the algorithms, and the techniques used to manipulate real world signals after they have been converted into a digital form. This includes a wide variety of goals, such as: enhancement of visual images, recognition of speech, compression of data for storage and transmission, etc. DSP包含数学算法，算法实现和用于现实世界信号转换成数字形式后的处理技术。

DSP包括各种各样的目标，如：提高视觉图像，语音识别，存储和传输的数据压缩，等
3 The channel capacity is a function of the probabilistic description of the output conditional on each possible input. Conversely, it is not possible to achieve low error probability at rates above the channel capacity.信道容量是在每个可能的输入输出条件概率描述的功能。

相反，它是不可能实现低错误率超过信道容量的概率.
4 The blocks of binary digits can be generalized into variable-length sequences of binary digits. We shall find that any given discrete source, characterized by its alphabet and probabilistic description, has a quantity called entropy associated with it.二进制位的块，可以概括为可变长度的二进制数字序列。

我们会发现，任何给定的离散源，其字母和概率描述的特点，有一个叫做熵与它相关的数量。

5 One approach to channel measurement is to allocate a certain portion of each transmitted packet for that purpose. During this period, a known probing sequence is transmitted and the receive users this known sequence either to estimate the current values for the taps in the discrete-time baseband model of the channel or to measure the actual paths in a continuous-time baseband model.通道测量的方法之一就是为此目的拨出一定比例的每个传输的数据包。

在此期间，一个已知的探测序列传输和接收用户这个已知序列估计通道的离散时间基带模型的当前值的水龙头，或在一个连续时间基带模型来衡量的实际路径。

6 I mage restoration is applied to the restoration of a known distortion for which an objective criterion can be applied.图像恢复被用于复原已知的失真，这个过程将使用一个客观的标准
7 In archeology, image processing methods have successfully restored blurred pictures that were the only available records of rare artifacts lost or damaged after being photographed.在考古学中，图像处理技术方法已成为成功恢复罕见文物丢失或损失块后唯一可用记录的模糊照片
8 A lot of information is required to specify the exact distribution of a random variable, and even more to specify the joint distribution of two or more variables.在指定一个随机变量的确定分布需要大量的信息如果指定两个或多个变量的联合分布则需要更多的信息
9 When feedback is used around an operational amplifier, the closed loop gain of the circuit is determined by a ratio involving the input and feedback impedances used.在理想运放的电器分析过程中使用在反相输入端零电压和零电流的约束条件简化电路分析。

10 Systems are defined to be stable if every bounded input excites a bounded output. The condition for discrete-time system to be stable is that all poles of H(x) lie inside the unit circle on the Z-plane.如果每一个有界输入激发有界的输出，那么可定义系统是稳定的，离散时间系统的稳定条件是H（x）几点都在Z坐标单位圆的内部。

中译英
1 Large communication system such as the Public Switched Telephone Network (PSTN) and the Internet have incredible complexity, made up of an enormous variety of equipment made by different manufactures at different times following different design principles.大型通信系统，如公用电话交换网（PSTN）和Internet，都是异常复杂的，它们由大量的、由不同厂商在不同时期按不同设计原则出来的不同设备所设计。

2 Some discrete sources generate finite segments of symbols, such as email messages, that are statistically undeleted to other finite segments that might be generated at other times.一些离散源产生的有限长符号，如电子邮件信息，它们在统计意义上是与其他时间所产生的有现场符号段无关的。

3 1G analog system for mobile communications saw two key improvements during the 1970s: the invention of the microprocessor and the digitization of the control link between the mobilephone and the cell site.20世纪70年代，1G 模拟制式的无线通信系统见证了两项重要的技术改进：微处理器的发明及无线电话和小区之间控制链路的数字化。

4 Thus, what we call in this book digital image processing encompasses processes whose inputs and outputs are image and, in addition, encompasses processes that extract attributes from images, up to and including the
recognition of individual objects.因此，书中所说的“数字图像处理”既包括输入/输出都是图像的过程，也包括从图像中提取特征等其他过程，直至对个体目标进行识别也属于本书的范畴。

5 Description, also called feature selection, deals with extracting attributes that result in some quantitative information of internet or are basic for differentiating one class of objects from another.图像描述也称为特征选取，是指从图像中提取某些特征，这些特征或者产生人们感兴趣的定量信息，或者作为区别不同目标类别的基础。

6 To process an analog signal digitally, it must first be discretized in time to yield a discrete-time signal and then quantized in amplitude to yield a digital signal.要以数字化的方式处理模拟信号，应先对模拟信号在时间上离散以产生离散时间信号，然后对其幅值量化以产生数字信号。

7 Frequency response will be flat and bandwidth infinite because AC will be simply a rapidly varying DC level to the ideal amplifier.对于理想放大器而言，交流只不过是快速变化的直流，所以其频率响应是一条水平直线，带宽无限。

8 In control and instrumentation applications, its practical value lies in the ease with which desired input impedance and gain values can be tailored to fit the requirements of the associated circuitry.在控制与仪器仪表应用中，反相放大器的实用价值在于，利用它可以很容易地调整所需的输入阻抗和增益值以适应相关电路的要求。

9 While superposition and convolution may sound a little abstract, there is an equivalent statement that will make it concrete: a system is a shift-invariant, linear system if and only if the responses are a weighted sum of the inputs.叠加与卷积听起来可能有些抽象，但具体可等效解释为：当且仅当系统的响应可表示为输入信号的加权和时，该系统才是线性时不变系统。

10 Due to the exact and all-encompassing nature of these laws in predicting electromagnetic phenomena, along with the great body of analytical and experimental investigations performed since then, we can consider the field of RF and microwave engineering a “mature discipline “at this time.由于麦克斯韦定律可准确预测各种电磁现象，加之后续进行的大量理论分析和实验研究工作，可以说射频/微波工程现在是一门成熟的学科。

问题
1 what is the impulse response function of the system? when characterizing a system, what kinds of system just need to measure only impulse response function?
δ(t)= 1 if t=0 a shift-invariant linear system
0 otherwise
2 in the transmission of digital signal, any noise and disturbance will affect the signals ,what kind of code is used for improving the reliability? please give a example.
This reliability can further be improved by using error-interleaved keed-solomon code. It is possible to correct 2400 bit log error(corresponding to 2mm scrateches)
3 what is the basic concept of image enhancement and image compression?
The idea behind enhancement techniques is to bring out detail that is obsouted image enhancement compression deals with techniques for reducing the storage required to save an image, or the bandwidth required to transmit it.
4 what are the technology features of three generations of mobile communications?
PDMA TDMA CDMA
5 in stand voice telephony, the voice is sampled 8000 times per second, the source coding bit rate is 64 Kbps, please figure out the quantized levels and how many bytes to represent?
256 levels 8 bit byte
6 Q=quantization, what is the equation stands for? Q(2.6+2.7)=Q(2.6)+Q(2.7)=3+3=6
Truncations or rounding
7 what are the two summing point restraints of operational amplifier with feedback circuits?
No current flows into either input terminal of the ideal operational amplifier, when negative feedback is applied around the ideal operational amplifier, the differential input voltage approaches zero.
8 what are properties of the liner system that define the linearity?
In mathematics, alinear map or function f(x) is a function which satisfies the following two properties.
9 what is the only one thing we need to measure when shift invariance system characterize?
The way the system responds to a unit impulse. This response is called the impulse response function of the system.
10 please figure the placing a binany inter face between conrce and channel, what is the source encoder?
The source encoder has the function of converting the input from its original form a sequence of bits.。