文档介绍：毕业设计(论文)
自适应均衡器的设计与仿真
摘要
在移动通信领域中,码间干扰始终是影响通信质量的主要因素之一。为了提高通信质量,减少码间干扰,在接收端通常采用均衡技术抵消信道的影响。由于信道响应是随着时间变化的,通常采用自适应均衡器。自适应均衡器能够自动的调节系数从而跟踪信道,成为通信系统中一项关键的技术。
本篇论文在对无线通信信道进行研究的基础上,阐述了信道产生码间干扰的原因以及无码间干扰的条件,介绍了奈奎斯特第一准则和时域均衡的原理。深入研究了均衡器的结构和自适应算法,在均衡器的结构中主要介绍了4种自适应均衡器结构即线性横向均衡器、线性格型均衡器、判决反馈均衡器和分数间隔均衡器,并对这几种结构进行了比较。对于系数调整算法主要介绍了常用的几种算法,包括LMS算法、RLS算法以及盲均衡常用的恒模算法(CMA),并讨论了它们各自的优缺点。最后选用线性横向均衡器结构与上述3种系数调整算法,利用MATLAB进行仿真,并对结果进行分析与比较。
关键字:自适应均衡器,LMS,RLS,CMA ,MATLAB
Abstract
In the field of munications, the inter-symbol interferences (ISI) is always one of the primary factor which effects transmission. Adaptive equalization is mainly solution of dealing with ISI. Equalizers are often used bat the influence of channels for munication’s quality and decreasing ISI in receivers. Sometimes, channel response varies due to time, the adaptive equalizer is always necessary. Equalizer coefficients can be automatically adjusted to track the channel as a munication system technology.
On the basis of studying on munication channel, this paper discusses the reasons of resulting inter-symbol interference (ISI) and without conditions, introduces Nyquist first rule and the theory of adaptive equalizers. The equalizer structures and the adaptive algorithm are particularly studied in this paper. Mainly introducing paring four adaptive equalizer structures, such as linear horizontal equalizer, line personality type equalizer, decision feedback equalizer, fractionally spaced equalizers. Then we research the algorithms of the adaptive equalizer which are often used, including LMS, RLS, CMA, and discuss their respective advantages and disadvantages. Finally, we choose different adaptive equalizer structures and algorithms, and use the MATALB tool to simulate, at the end of this paper we analyze pare the results.
Keywords: adaptive equalizer, LMS, RLS, CAM, MATLAB
目录
摘要 I
ABSTRACT II
目录 III
第一章绪论 1
1
(外)研究现状 1
2
第二章信道、码间干扰及均衡技术 3
信道 3
恒参信道 4
2