现代数字与模拟通信系统(第4版)(英文版) [Modern Digital and Analog Communication Systems,International Fourth Edition] pdf epub mobi txt 电子书 下载
编辑推荐
关于最新技术进步和应用的讨论。新增了介绍扩频通信、频率选择性信道和OFDM系统的章节(第11章和第12章)。新增的和更新过的可供学生实践的MATLAB实例。灵活的组织形式(参见《现代数字与模拟通信系统(第4版)(英文版)》前言)容纳了各种课程框架,包括一学期、两个学期、一季度及两个季度。尽可能给出直观的讲解(而不仅仅是证明),进而启发式地解释理论成果。包含CDMA、OFDM.均衡、软解码、Turbo码、LDPC等新内容。
内容简介
《现代数字与模拟通信系统(第4版)(英文版)》是电子工程领域中的理想的通信系统入门教材。作者首先介绍了信号与系统的基础理论和通信的核心问题,然后给出了设计和分析数字通信系统的工具。内容涵盖基本的通信理论、必要的数学基础及扩频通信等现代通信技术。启发性的讲解方法、精心挑选的例题和更新的MATLAB练习使本书成为易于被学生理解和接受的通信系统理论与应用的入门教材。
《现代数字与模拟通信系统(第4版)(英文版)》作者长期从事相关领域的科研和教学工作,书中系统介绍从调制解调等通信基本理论到OFDM等现代通信技术的内容,包含概率论和随机过程的基本知识,增加了CDMA.OFDM.均衡、软解码、Turbo码和LDPC等近年来通信技术领域的热点技术,并包含大量现实生活中的实例。
作者简介
B·P·拉兹,美国加利福尼亚大学萨克拉门托分校电机与电子工程系名誉教授,IEEE会士。
丁峙,美国加利福尼亚大学戴维斯分校电气与计算机工程系教授,IEEE会士。IEEE电路与系统协会2004~2005年度杰出讲师,IEEE通信协会2008~2009年度杰出讲师。
内页插图
目录
第1章 简介
第2章 信号与信号空间
第3章 信号的分析和传输
第4章 幅度调制与解调
第5章 角度调制与解调
第6章 采样和模数转换
第7章 数字传输原理
第8章 概率论基础
第9章 随机过程和谱分析
第10章 数字通信系统的性能分析
第11章 扩频通信
第12章 线性信道失真下的数字通信
第13章 信息论介绍
第14章 纠错编码
第15章 纠错编码
附录A 一些信号集的正交性
附录B 柯西-施瓦茨不等式
附录C 矢量集的格拉姆-施密特正交化
附录D 矩阵的基本性质和运算
附录E 其他
精彩书摘
As noted earlier, channel noise is a major factor limiting communication performance because it is random and cannot be removed by prediction. On other other hand, randomness isalso closely associated with the desired signals in communications. Indeed, randomness is theessence of communication. Randomness means unpredictabiliry, or uncertainty, of a source message. If a source had no unpredictability, like a friend who always wants to repeat the samestory on "how I was abducted by an alien," then the information would be known before handand would contain no information. Similarly, if a person winks, it conveys some informationin a given context. But if a person winks continuously with the regularity of a clock, the winks convey no information. In short, a predictable signal is not random and is fully redundant.Thus, a message contains information only if it is unpredictable. Higher predictability meanshigher redundancy and, consequently, less information. Conversely, more unpredictable or lesslikely random signals contain more information.
Source coding reduces redundancy based on the predictability of the message source. The objective of source coding is to use codes that are as short as possible to represent the sourcesignal. Shorter codes are more efficient because they require less time to transmit at a givendata rate. Hence, source coding should remove signal redundancy while encoding and transmitting the unpredictable, random part of the signal. The more predictable messages contain more redundancy and require shorter codes, while messages that are less likely contain more information and should be encoded with longer codes. By assigning more likely messages withshorter source codes and less likely messages with longer source codes, one obtains more efficient source coding. Consider the Morse code, for example.ln this code, various combinations of dashes and dots (code words) are assigned to each letter. To minimize transmission time,shorter code words are assigned to more frequently occurring(more probable) letters (suchas e,t, and a) and longer code words are assigned to rarely occurring (less probable) letters(such as x, q, and z). Thus, on average, messages in English would tend to follow a knownletter distribution, thereby leading to shorter code sequences that can be quickly transmitted.This explains why Morse code is a good source code.
It will be shown in Chapter 13 that for digital signals, the overall transmission time is minimized if a message(or symbol) of probability P is assigned a code word with a lengthproportional to log (1/P). Hence, from an engineering point of view, the information of amessage with probability P is proportional to log (1/P). This is known as entropy (source)coding.
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前言/序言
现代数字与模拟通信系统(第4版)(英文版) [Modern Digital and Analog Communication Systems,International Fourth Edition] 电子书 下载 mobi epub pdf txt
现代数字与模拟通信系统(第4版)(英文版) [Modern Digital and Analog Communication Systems,International Fourth Edition] pdf epub mobi txt 电子书 下载