匹配滤波器的研究与设计

毕业设计(论文)

课题名称匹配滤波器的研究与设计

学生姓名刘燕

学号**********

系、年级专业信息工程系、通信工程

指导教师陈延雄

职称工程师

2009年5月22日

摘要

本文针对扩频接收机中伪码捕获部分为研究重点，分析了几种基匹配滤波器实现方于FPGA的常用案，其中包括：直接形式的匹配滤波器、转置结构的匹配滤波器、采用分布式算法的匹配滤波器和折叠式匹配滤波器。通过比较这些方案的优缺点，最终选定了以折叠式匹配滤波器为最优方案来进行设计。折叠式匹配滤波器实际上就是以静止的本地扩频码作为累加器的系数，匹配滤波器相关过程就相当于接收信号滑过本地序列，当滑动到两个序列相位对齐时，就必有一个相关峰值输出。该匹配滤波器采用VHDL语言，通过模块划分来进行设计，整个过程都在Xilinx公司开发的ISE集成软件系统中完成，最后在Modelsim仿真软件上进行了各个模块的仿真。本论文所设计的折叠式匹配滤波器，能够根据实际需要来设置不同的扩频码长度，很好的完成伪码的相关捕获效果。该折叠式匹配滤波器结构能够节省FPGA资源，提高伪码捕获时间和效率，有很好的实际效果。

关键词：匹配滤波器；M序列；伪码捕获；折叠式FIR结构；FPGA

ABSTRACT

Based on this background , making the PN code capture part as a point of the spread spectrum receiver , this paper analyze several common used Matched Filter programs on FPGA , including : the direct form of matched filter , the transposed structure of matched filter , the distributed arithmetic structure of matched filter , and folded structure of matched filter . Compared with the advantages and the disadvantages of these programs , finally we choose the folded structure of matched filter as the best one to complete this design . The folded filter is actually using the PN code as the accumulator coefficients , and then , matched filter correlation process is equivalent to the receiving signal spreading the PN code . When the sliding of two phase sequence is the same , this implies that making a result of correlation . The designs of the matched filter using VHDL and modules . The whole process completed in the development of the company Xilinx ISE Integrated Software System . Finally , every modules simulated in the Modelsim simulation software . The design on this paper , according to the actual need , can set up a different PN code length , and make a good effect on the PN code capture of the spread spectrum receiver . The folded matched filter can reduce the cost on FPGA resources or the PN code capture time , and improve the efficiency of the capture process , it also can make a very good practical effects .

Key words:Matched filter ；M series；Acquisition of Pseudo-code；Folded FIR structure；Transposed FIR structure；FPGA

目录

摘要........................................................................................................................I ABSTRACT ....................................................................................................... II 目录................................................................................................................... III 第1章绪论 (1)

1.1课题来源及研究意义 (1)

1.2匹配滤波器的发展及研究现状 (1)

1.3本文的主要工作 (2)

第2章匹配滤波器理论 (3)

2.1匹配滤波器概述 (3)

2.2匹配滤波器在扩频接收机中的应用 (5)

第3章扩频接收机中匹配滤波器的FPGA设计 (15)

3.1方案采用说明 (15)

3.2匹配滤波器模块划分 (18)

3.3匹配滤波器各个模块的实现 (24)

第4章电路综合与仿真结果分析 (37)

4.1仿真综述 (37)

4.2M ODELSIM仿真操作流程 (37)

4.3匹配滤波器各个模块的仿真数据分析 (40)

4.4匹配滤波器整体系统性能 (45)

总结 (47)

参考文献 (49)

致谢 (51)

附录 (52)

附录Ⅰ (52)

附录Ⅱ (56)

附录Ⅲ (57)