xilinx_CORDIC算法(非常经典)
FPGA有关的cordic讲解，xilinx公司ppt型的详细讲解，中文。从原理到实现（模型的建立等）。简介目前的具有许多乘法器和加法器。然而各种各样的通信技术和矩阵算法则需要三角函数、平方根等的运算如何在上执行这些运算可以使用查找表或是迭代法本节介绍了算法这是一个移位相加算法允许计算不同的三角函数例如0.0.0包括除法和对数酾数在内的其它函数。xⅫNX关于算法的细节问题,可参见下面的材料技术并不是什么新鲜的东西。事实上它可以追溯到年由发表的一篇文章。在上个世纪五十年代,在大型实际的计算机中的实行移位相加受到了当时技术上的限制,所以使用变得非常必要。到了七十年代,和其他公司出产了手持计算器,许多计算器使用一个内部单元来计算所有的三角函数(了解这件事的人们一定还记得,那时求一个角度的正切值需要延迟大约1秒中)二十世纪八十年代,随着高速度乘法器与带有大存储量的通用处理器的出现, CORDIC算法变得无关紧要了。然而在二十一世纪的今天,对于来说,定是在应用中(诸如多输入多输出(波束形成以及其他自适应系统)计算三角函数的备选技术。wwwsteepestascenCO1笛卡尔坐标平面旋转在坐标平面上将点(,)旋转0角度到点(,)的标准方法如下所示00这被称为是平面旋转、向量旋转或者线性矩阵代数中的旋转。xⅫNX上面的方程组同样可写成矩阵向量形式00例如一个相移为wwwsteepestascenCO1伪旋转通过提出因数,方程可写成下面的形式000(0)如果去除0项,我们得到伪旋转方程式0)6(0)即旋转的角度是正确的,但是与的值增加9倍由于所以模值变大。注意我们并不能通过适当的数学方法去除0项然而随后我们发现去除θ项可以简化坐标平面旋转的计算操作。xⅫNX在坐标平面中0因此经过伪旋转之后,向量的模值将增加0倍。向量旋转了正确的角度但模值出现错误。wwwsteepestascenCO1方法方法的核心是伪旋转角度θ,其中θ。故方程为下面的表格指出用于算法中每个迭代的旋转角度精确到位小数xⅫNX在这里,我们把变换改成了迭代算法。我们烀各种可能的旋转角度加以限制,使得对任意角度θ的旋转能够通过一系列连续小角度的旋转迭代来完成。旋转角度遵循法则:0,遵循这样的法则,乘以正切项变成了移位操作。前几次迭代的形式为第次迭代旋转第次迭代旋转第次迭代旋转等很显然,每次旋转的方向都影响到最终要旋转的累积角度。在≤日的范围内的任意角度都可以旋转。满足法则的所有角度的总和0为。对于该范围之外的角度,可使用三角恒等式转化成该范围内的角度。当然,角分辨率的数据位数与最终的精度有关。。因此,在次旋转以后,为了标定伪旋转的幅度,要求乘以一个系数角分辨率的数据位数对最终的旋转精度非常关键。wwwsteepestascenCO1
- 2020-11-29下载
- 积分：1
Principles of Mobile Communication Third Edition
Gordon L. Stüber著，为英文原文第三版。其第二版已经翻译成中文，即为移动通信原理（第二版），由电子工业出版社出版，但翻译水平很差。Gordon L. StuberPrinciples of mobileCommunicationThird edition② SpringerGordon L. StuberGeorgia Institute of TechnologyAtlanta gaUSAstuber @ece gatech. eduISBN978-1-4614-0363-0e-ISBN978-1-46140364-7DOI10.1007/978-1-46140364-7Springer New York Dordrecht Heidelberg londonLibrary of Congress Control Number: 2011934683C Springer Science+Business Media, LLC 2002, 2011All rights reserved. This work may not be translated or copied in whole or in part without the writtenpermission of the publisher(Springer Science+ Business Media, LLC, 233 Spring Street, New York,NY 10013, USA), except for brief excerpts in connection with reviews or scholarly analysis. Use inconnection with any form of information storage and retrieval, electronic adaptation, computer softwareor by similar or dissimilar methodology now known or hereafter developed is forbiddenThe use in this publication of trade names, trademarks, service marks, and similar terms, even if they arenot identified as such, is not to be taken as an expression of opinion as to whether or not they are subjectto proprietary rightsPrinted on acid-free paperSpringerispartofSpringerScience+businessMedia(www.springer.com)To Alana, our son nickolasmy father lothar Stuiberand my late mother Beatrice stiiberPrefacePrinciples of Mobile Communication, third edition, is a major revision of thesecond edition. Like its earlier editions, this book provides a mathematicallyrigorous overview of physical layer wireless communications. The basic pedagogicmethodology is to include fully detailed derivations from first principles. The text isintended to provide enough principle material to guide the novice student, whilit the same time having plenty of detailed material to satisfy graduate studentsinclined to pursue research in the area. The book is intended to stress the principlesof wireless communications that are applicable to a wide array of wireless standardsIt is intended to serve as a textbook and reference for graduate students, and a usefulreference for practicing engineersOrganization of the bookChapter 1 begins with an overview that is intended to introduce a broad array ofissues relating to wireless communications. Included is a brief description of theevolution of various wireless standards, the basic concepts of cellular frequencyreuse, the land mobile radio propagation environment, link budgets, and coverageand capacity of cellular radio systemsChapter 2 provides an extensive treatment of radio propagation, since goodunderstanding of the physical wireless channel is essential for the developmentand deployment of wireless systems. The chapter begins with a treatment ofthe narrow-band faded envelope for conventional fixed-to-mobile channels foundin cellular radio systems, mobile-to-mobile channels found in mobile ad henetworks, and multiple-input multiple-output (MIMO) channels where multipleantennas are used at both the transmitter and receiver to achieve high capacity afterconsidering the narrow-band channel, we consider the statistical treatment of wide-band channels. The emulation of wireless channels is essential for the developmentand testing of wireless systems, and the chapter provides a detailed discussion ofchannel simulation techniques. Finally, the chapter concludes with a discussion ofshadowing and path loss models for land mobile radio environmentsPreraceChapter 3 provides a detailed treatment of co-channel interference which is therimary impairment in spectrally efficient cellular frequency reuse systems. Veryoften the receivers in such systems are affected by multiple co-channel interferersand the probability distribution of the total interfering power is considered. Thchapter also considers the link outage performance due to co-channel interferencein a variety of wireless environmentsChapter 4 covers the various types of modulation schemes that are used in mobilecommunication systems along with their spectral characteristics. The chapter beginswith the mathematical representation of bandpass modulated signals, along withNyquist pulse shaping. Later, a large variety of modulation schemes used in wirelesssystems are considered, including both single-carrier and multi-carrier modulation,and both linear and nonlinear modulation techniques This is followed by a treatmentof the power density spectrum of modulated signals. Although quite mathematicalin nature, power spectrum is an important topic, since wireless systems are requiredto operate within a specified out-of-band emission maskChapter 5 discusses the error probability performance of various digital modulation schemes on narrow-band fat fading channels. The performance is evaluatedwith a variety of receiver structures, including coherent detectors, differentialcoherent detectors and noncoherent detectorsChapter 6 includes a treatment of multi-antenna techniques for combatingenvelope fading. The chapter includes a discussion of various diversity combiningtechniques for coherent, differentially coherent, and noncoherent receiver detectionof signals on fading channels with additive white gaussian noise. also consideredis optimal combining which is effective when the primary additive impairment isco-channel interference rather than noise. Finally, the chapter considers the use ofmultiple antennas at the transmitter in the context of classical beam-forming andtransmit diversityChapter 7 provides an extensive treatment of digital signaling on intersymbolinterference(ISI) channels that are typical of broadband land mobile radio systemsThe chapter begins with the characterization of Isi channels and goes on todiscuss techniques for combating ISI based on symbol-by-symbol equalization andsequence estimation. Later, error probability for maximum likelihood sequenceestimation is considered. The chapter concludes with a discussion of co-channeldemodulation for the purpose of mitigating co-channel interference on Isi channelsChapter 8 covers error control coding techniques for wireless systems. Thechapter begins with a discussion of basic block coding including space-time blockcodes Convolutional coding is considered next along with the Viterbi and BCJRalgorithms for decoding convolutional codes, followed by trellis coded modulationThe chapter then provides a detailed discussion on the design and performanceanalysis of convolutional and trellis codes for awgn channels, and interleaved fatfading channels, and fading isi channels. Later, space-time trellis codes are treatedand the chapter concludes with Turbo codinChapter 9 is devoted to spread spectrum techniques The chapter begins with anintroduction to direct sequence and frequency hop spread spectrum. This is followedy a detailed treatment of spreading sequences. Also included is a discussionPrefaceof the effects of tone interference on direct sequence spread spectrum, and theRAKE receiver performance on wide-band channels. The chapter wraps up witha discussion of cdma multiuser detectionChapter 10 is devoted to multi-carrier techniques. It considers the performanceof ofdm on frequency-selective channels and considers the effect of residualISI and problem of residual ISI cancellation. Later, the chapter examines singlecarrier frequency-domain equalization(SC-FDE)techniques. This is followed by atreatment of orthogonal frequency division multiple access (OFDMA)on both theforward and reverse links. The chapter concludes with a discussion of single-carrierfrequency division multiple acceSs (SC-FDMA)Chapter 11 considers frequency planning techniques for cellular systems. Thechapter begins with a discussion of cell sectoring, cell splitting, and reuse partition-ing. Later, the chapter considers radio planning for OFDMa cellular systems. Thisis followed by hierarchical overlay/underlay architectures based on cluster planningFinally, the chapter wraps up with macrodiversity TDMA cellular architecturesChapter 12 considers CDMa considers CDMA cellular systems, consideringtopics such as capacity and power control This is followed by a discussion ofhierarchical macrodiversity CDMa architectures and their performanceChapter 13 is devoted to cellular radio resource management. The chapter beginswith an introduction to basic hard and soft handoff. Later, the chapter considers theimportant problem of link quality evaluation, including signal strength averaging,velocity estimation, and velocity adaptive hard handoff algorithms later, a detailedanalysis of hard and soft handoff is provided. Finally, the chapter wraps up withmethods for estimating received carrier-to-interference plus noise ratio(CINR)The Appendix includes a brief and focused tutorial discussion of probabilityand random processes. A good understanding of the material in the Appendix isessential, since the concepts are widely used throughout the textUSing This Book for InstructionThe book has been developed from a graduate-level course on physical wirelesscommunications that I have taught at Georgia Tech since 1993. Normally, I prefera graduate-level course in digital communications as a prerequisite for this courseHowever, such a prerequisite may be waived to the extent that there is extensivebackground material in each chapter. A course may cover the introductory materialin each chapter and skip the more specialized material. In my own classes, I alwaystry to judge the mathematical level of the students early and adapt accordinglyThe book obviously contains far too much material to be taught in a onesemester course. However, i believe that it can serve as a suitable text in mostsituations through the appropriate instructor selection of background sections. Myown preference for a one semester course is to include the following material inorder: Chap. 1, Chap 2(skipping the more advanced material), and the first twosections of Chap 3. In moving to modulation waveforms in Chap. 4, an instructormay have to treat/assume basic signal-space representation. However, most students
- 2020-12-09下载
- 积分：1
