数字媒体专业英语（第2版）

（1）知识介绍系统。根据数字媒体技术的跨学科特点，系统介绍其基本理论与知识。
　　（2）结构编排完整。每篇课文都附有词汇、习题、译文等。
　　（3）信息材料新颖。所选素材具有很强的代表性、时代性、实用性、参考性。
　　（4）配有电子教案。为教师教学、学生自学提供方便。 

本书旨在让学生掌握较多相关专业英语词汇和数字媒体的基本概念，为阅读专业文献和书籍打下坚实的基础，同时为在以后工作中解决与专业英语相关的问题提供必要的知识保证。
　　本书结构编排完整、信息材料新颖。首先简单介绍了专业英语的翻译方法；*部分阐述数字媒体相关概念，包括多媒体综述、数字图像处理、数字音频、媒体资产管理、虚拟现实技术等内容；第二部分对常用的数字媒体应用软件进行介绍，如Photoshop、Flash、Dreamweaver、3ds Max、Premiere、After Effects等；第三部分介绍包括数据传输技术、光纤技术、无源光网络技术、电视原理、电视接收机在内的电信与通信技术；第四部分阐述计算机系统构成；第五部分列举常用的编程语言，如Java、ActionScript、C 等；第六部分介绍计算机网络的概念、应用及网络安全相关知识。每篇课文都配有习题及参考译文，供相关专业的师生参考。

         目  录
Part 0  专业英语翻译方法    1
0.1  专业英语翻译概述    1
0.2  词的翻译    4
0.3  长句的翻译    23
0.4  文章的翻译    24
Part 1  Digital Media    26
Text 1:  Multimedia—An Overview    26
Text 2:  An Introduction to Digital Image Processing    34
Text 3:  Digital Audio    41
Text 4:  Asset Management    48
Text 5:  Virtual Reality and Applications    53
Part 2  Digital Media Application Software    58
Text 1:  An Introduction to Photoshop    58
Text 2:  Making Movie Clips with Flash    60
Text 3:  An Introduction to Dreamweaver    65
Text 4:  The Model Types of 3ds Max    72
Text 5:  Premiere Pro’s Windows    76
Text 6:  Workspaces and Panels of After Effects    84
Part 3  Communication and Telecommunication Technology    89
Text 1:  Signals and Systems    89
Text 2:  Data Communication    92
Text 3:  Data Transmission Media    95
Text 4:  Switching Technologies    98
Text 5:  ATM    101
Text 6:  Fiber Optics    104
Text 7:  Passive Optical Networks (PONs)    107
Text 8:  Television: Basic Principles    112
Text 9:  Television Receivers    116
Part 4  Computer Systems    124
Text 1:  About Computers    124
Text 2:  Computer Hardware    129
Text 3:  Computer Software    136
Text 4:  Operating System    145
Text 5:  Creating a LAMP server with the Raspberry Pi    153
Part 5  Programming Languages    157
Text 1:  About Programming Languages    157
Text 2:  C    161
Text 3:  C     166
Text 4:  Java    171
Text 5:  ActionScript Basics    178
Part 6  Computer Network    185
Text 1:  About Computer Networks    185
Text 2:  Application of Computer Networks    191
Text 3:  Network Security    198
Text 4:  Introduction to HTML5 Canvas    205
附录A  参考译文    213
部分  数字媒体    213
第二部分  数字媒体应用软件    228
第三部分  通信和电信技术    243
第四部分  计算机系统    258
第五部分  编程语言    277
第六部分  计算机网络    294
附录B  词汇表    313
参考文献    333

         前  言
　　专业英语教学是大学英语教学及专业课教学的重要组成部分，是帮助和促进学生继续学习英语并学以致用的有效途径。而数字媒体代表着一个文理融合的全新领域，体现了技术与人文艺术的融合。
　　提起数字媒体，人们往往想到媒体行业，其实数字媒体的应用绝不仅仅局限于媒体。随着计算机技术、网络技术和数字通信技术的高速发展与融合，传统的广播、电影快速地向数字音频、数字视频、数字电影方向发展，与日益普及的计算机动画、虚拟现实等构成了新一代的数字传播媒体。因此，本教材适合数字媒体技术，计算机、通信电子，以及相关专业的大学本科、独立学院、高职高专的学生使用，也可供广大工程技术人员学习和参考。
　　通过“数字媒体专业英语”课程的学习，学生能掌握较多相关专业英语词汇和数字媒体的基本概念，为阅读专业文献和书籍打下坚实的基础，同时为在以后工作中解决与专业英语相关的问题提供必要的知识保证。本课程的目的是使学生不仅能学到专业英语词汇，扩大知识面，同时能掌握用英语表达专业知识的方法，提高阅读及理解专业英文资料的能力，掌握专业文献翻译的方法和技巧。
　　本教程的课文包括专业英语翻译方法、数字媒体、数字媒体应用软件、平面设计理论、通信和电信技术、计算机系统、编程语言、计算机网络等专业知识，取材丰富，所选篇目具有代表性。首先简单介绍了专业英语的翻译方法；部分阐述数字媒体相关概念，包括多媒体综述、数字图像处理、数字音频、媒体资产管理、虚拟现实技术等内容；第二部分介绍常用的数字媒体应用软件，如Photoshop、Flash、Dreamweaver、3ds Max、Premiere、After Effects等；第三部分介绍包括数据传输技术、光纤技术、无源光网络技术、电视原理、电视接收机在内的电信与通信技术；第四部分阐述计算机系统构成；第五部分列举常用的编程语言，如Java、ActionScript、C 等；第六部分介绍计算机网络的概念、应用以及网络安全相关知识。
　　本书的主要特点如下：
　　（1）知识介绍系统。根据数字媒体技术的跨学科特点，系统介绍其基本理论与知识。
　　（2）结构编排完整。每篇课文都附有词汇、习题、译文等。
　　（3）信息材料新颖。所选素材具有很强的代表性、时代性、实用性、参考性。
　　（4）配有电子教案。为教师教学、学生自学提供方便。
　　本书Part 0～Part 3由周灵编写，Part 4由周灵、薛雁丹共同编写，Part 5、Part 6由薛雁丹编写，周灵、薛雁丹共同完成附录的整理工作，单园园完成全书的校对工作。
　　本书在编写过程中，得到了苑文彪老师的热情指导与帮助，在此表示感谢！
　　本书在选材时，参考了国内外有关书籍和资料，在此对这些文献的作者表示诚挚的敬意和谢意！
　　由于信息技术发展日新月异，新的知识在不断扩展更新，加上编者的学识和水平有限，书中疏漏、错误之处在所难免，敬请广大读者不吝批评指正。
　　编   者
　　2018年10月于南京

Part 3  Communication and Telecommunication
Technology
Text 1: Signals and Systems
　　This textbook provides an introduction to the tools and mathematical techniques necessary for understanding and analyzing both continuous-time and discrete-time linear systems. We have attempted to give an insight into the application of these tools and techniques for solving practical engineering problems. Our philosophy has been to adopt a systems approach throughout the book for the introduction of continuous-time signal and system analysis, rather than use the framework of traditional circuit theory. We believe that the systems viewpoint provides a more natural approach to introducing this material in addition to broadening the horizons of the student. Furthermore, the topics of discrete time signal and system analysis are most naturally introduced from a systems viewpoint, which lends overall consistency to the development. We have, of course, relied heavily on the students’ circuit theory background to provide illustrative examples.
　　The organization of the book is straightforward. The first six chapters deal with continuous-time linear systems in both the time domain and the frequency domain. The principal tool developed for time-domain analysis is the convolution integral. Frequency-domain techniques include the Fourier and the Laplace transforms. An introduction to state variable techniques is also included. The remainder of the book deals with discrete-time systems including z-transform analysis techniques, digital filter analysis and synthesis, and the discrete Fourier transform and fast Fourier transform (FFT) algorithms.
　　This organization allows the book to be covered in two three-semester-hour courses, with the first course being devoted to continuous-time signals and systems and the second course being devoted to discrete-time signals and systems. Alternatively, the material can be used as a basis for three quarter length courses. With this formats the first course would cover time and frequency-domain analysis of continuous-time systems. The second course would cover state variables, sampling, and an introduction to the z-transform and discrete-time systems. The third course would deal with the analysis and synthesis of digital filters and provide an introduction to the discrete Fourier transform and its applications.
　　The assumed background of the student is mathematics through differential equations and the usual introductory circuit theory course or courses. Knowledge of the basic concepts of matrix algebra would be helpful but is not essential. Appendix A is included to bring together the pertinent matrix relations that are used in Chapters 5 and 6. We feel that in most electrical engineering curricula the material presented in this book is best taught at the junior level.
　　We begin the book by introducing the basic concepts of signal and system models and system classifications. The idea of spectral representations of periodic signals is first introduced in Chapter 1 because we feel that it is important for the student to think in terms of both the time and the frequency domains from the outset.
　　The convolution integral and its use in fixed, linear system analysis by means of the principle of superposition are treated in Chapter 2. The evaluation of the convolution integral is treated in detailed examples to provide reinforcement of the concepts. Calculation of the impulse response and its relation to the step and ramp responses of a system are discussed. Chapter 2 also contains optional sections and examples regarding writing the governing equations for lumped, fixed, linear systems and the solution of linear, constant coefficient differential equations. These are intended as review and may be omitted without loss of continuity.
　　The Fourier series and Fourier transform are introduced in Chapter 3. We have emphasized the elementary approach of approximating a periodic function by means of a trigonometric series and obtaining the expansion coefficients by using the orthogonality of sines and cosines. We do this because this is the first time most of our students have been introduced to Fourier series. The alternative generalized orthogonal function approach is included as a nonrequired reading section at the end of this chapter for those who prefer it. The concept of the transfer function in terms of sinusoidal steady-state response of a system is discussed in relation to signal distortion. The Fourier transform is introduced next, with its applications to spectral analysis and systems analysis in the frequency domain. The concept of an ideal filter, as motivated by the idea of distortion-less transmission, is also introduced at this point. The Gibbs Phenomenon, window functions, and convergence properties of the Fourier coefficients are treated in optional closing sections.
　　The Laplace transform and its properties are introduced in Chapter 4. Again, we have tried to keep the treatment as simple as possible because this is assumed to be a first exposure to the material for a majority of students, although a summary of complex variable theory is provided in Appendix B so that additional rigor may be used at the instructor’s option. The derivation of Laplace transforms from elementary pairs is illustrated by example, as is the technique of inverse Laplace transform using partial fraction expansion. Optional sections on the evaluation of inverse Laplace transforms by means of the complex inversion integral and an introduction to the two-sided Laplace transform are also provided.
　　The application of the Laplace transform to network analysis is treated in detail in     Chapter 5. The technique of writing Laplace transformed network equations by inspection is covered and used to review the ideas of impedance and admittance matrices, which the student will have learned in earlier circuit courses for resistive networks. The transfer function is treated in detail, and the Routh test for determining stability is presented. The chapter closes with a treatment of Bode plots and block diagram algebra for fixed, linear systems.
　　In Chapter 6, the concepts of a state variable and the formulation of the state variable approach to system analysis are developed. The state equations are solved using both time-domain and Laplace transform techniques, and the important properties of the solution are examined. Finally, as an example, we show how the state-variable method can be applied to the analysis of circuits.
　　The final three chapters provide coverage of the topics of discrete-time signal and system analysis.
　　A complete solutions manual, which contains solutions to all problems, is available from the publisher as an aid to the instructor. Answers to selected problems are provided in Appendix E as an aid to the student.
　　The authors wish to express their thanks to the many people who have contributed, both knowingly and unknowingly, to the development of this textbook. First, thanks go to our long-suffering students, who have been forced to study from our notes, often while they were still in various stages of development. Their many comments and criticisms have been invaluable and are gratefully appreciated. Many of our colleagues in the Electrical Engineering Department at the University of Missouri-Rolla taught courses that used the book in note form and provided many suggestions for improvement. In this regard, we thank Professors Gordon E. Carlson, Kenneth H. Carpenter, and some others. Professor Carlson critically reviewed much of the manuscript and provided valuable suggestions for improvement. Additionally, we would like to thank the reviewers at other institutions who provided valuable criticism. However, any shortcomings of the final result are solely the responsibility of the authors. A most sincere thanks goes to our secretaries whose great care and expert typing skills allowed us to generate the final manuscript with a minimum of headaches. The National Engineering Consortium is also due thanks since it was through their series of seminars that much of the material in Chapters 7 and 8 was originally taught.