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毕业设计(论文)说明书
题 目：GMSK调制器的FPGA实现 学 院： 专 业： 学生姓名： 学 号： 指导教师：
职 称：
题目类型：?理论研究 ?实验研究 ?工程设计 ?工程技术研究 ?软件开发
2012年 5 月 10 日
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摘 要
GMSK是当前现代数字调制技术领域的研究热点之一,它通过在MSK调制器之前加入一个高斯低通滤波器来获得更加紧凑的频谱, GMSK（高斯最小移频键控）信号优良的频谱特性在跳频通信中有广阔的应用前景。本文分析了GMSK调制器的设计理论，并在FPGA上加以实现。仿真结果表明，这种数字实现结构产生的GMSK基带信号具有良好的功率谱，同时能够有效避免I/Q两条支路信号幅度及正交载波相位失衡。高斯滤波最小频移键控，这是GSM系统采用的调制方式。数字调制技术是数字峰窝移动通讯系统空中接口的重要组成部分。GMSK提高了数字移动通信的频谱利用率和通信质量。本设计基于GMSK调制器相关原理，利用MATLAB/FPGA验证自主设计的GSMK调制电路，在以上基础上，自主设计实现了gmsk调制技术的乘法模块、加法模块和抽样判决模块等，通过信号输出比较分析，验证了gmsk调制算法，达到了系统设计要求，取得了良好效果。
关键词：GMSK；FPGA；MATLAB；数字调制
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Abstract
GMSK is the current modern digital modulation technology of research in the field of one of the hotspots, It through before joining a MSK modulator in gaussian low-pass filter to get more compact spectrum, GMSK (gaussian minimum frequency shift keying) signal excellent spectrum characteristics in frequency hoppingcommunication have broad application prospects. This paper analyzes the design theory GMSK modulator, And FPGA to realization. Simulation results show that, This digital realization structure produces GMSK baseband signal has good power spectrum, Also can effectively avoid two branch signal amplitude and orthogonal carrier phase unbalanced. Gaussian filtering minimum FSK, This is GSM system USES modulation mode. Digital modulation technique is digital peak nest of mobile communication system is an important part of the air interface. GMSK improved digital mobile communication frequency spectrum availability and communication quality. This design based on the GMSK modulator related principles, use of MATLAB/FPGA validation GSMK modulation circuit of independent design, On the basis of the above, Independent design and realize the multiplication of GMSK modulation technology, addition module and sampling module judgment module, Through comparative analysis of its output signal, Verify the algorithm GMSK modulation, Reached system design requirements, Achieved good results.
Key words: GMSK；FPGA；MATLAB；digital modulation
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目 录
1 引言 ................................................................................................................. 1
1.1 GMSK的介绍 ........................................................... 1 1.1.1 历史 ............................................................... 3 1.1.2 应用 ............................................................... 3 1 .2 FPGA介绍 ............................................................ 4 1.2.1背景 ................................................................ 4 1.2.2 FPGA芯片结构 ....................................................... 5 1.2.3 FPGA的基本特点 ..................................................... 8 1.2.4 FPGA配置模式 ....................................................... 8 1.2.5 FPGA的应用 ......................................................... 9 1.2.6最新应用 ........................................................... 10
2 本文的主要结构和内容提要 ......................................................................... 11 3 GMSK信号及其调制方案 .............................................................................. 12
3.1 概述 ................................................................. 12 3.2 调制方式 ............................................................. 12 3.2.1 最小频移键控(MSK) .................................................. 12 3.3 高斯最小移频键控（GMSK） ............................................. 12 3.4 GMSK信号的分析 ...................................................... 14 3.4.1 GMSK调制信号的相位路径 ............................................ 14 3.4.2 数字信号功率谱密度的研究 ........................................... 15 3.4.3 已调波占用带宽 ..................................................... 15 3.4.4 码间干扰ISI ....................................................... 16 3.5 GMSK调制器及其实现 .................................................. 16 3.5.1 差分编码 ........................................................... 17 3.5.2 高斯低通滤波器 ..................................................... 18
4 GMSK调制器的实现方案及其比较 .............................................................. 18
4.1 传统的实现方法 ....................................................... 18 4.2全数字实现方法 ....................................................... 19 4.3 GMSK调制原理结构 .................................................... 20 4.3.1 2FSK调制原理 ...................................................... 20 4.3.2 MSK调制原理 ....................................................... 21
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4.3.3 GMSK调制原理 ...................................................... 22
5 GMSK调制器的FPGA实现 ............................................................................ 23 6 调制的仿真及调试分析 ............................................................................... 24
6.1 仿真介绍 ............................................................. 24 6.2 数字通信系统的模型 ................................................... 25 6.3 数字通信系统的仿真 ................................................... 25 6.3.1仿真工具软件 ....................................................... 25 6.4 PSK,MSK,GMSK调制方式的仿真和分析 .................................... 28 6.5 软件调试 ............................................................. 32 6.5.1 差分模块 ........................................................... 32 6.5.2 加权模块 ........................................................... 33 6.5.3载波调制相加模块 ................................................... 34 6.5.4 顶层模块 ........................................................... 34 6.6 硬件调试 ............................................................. 35
7 总结 ................................................................................................................. 37 参考文献 ............................................................................................................. 38 附 录 ................................................................................................................. 39