基于MATLAB的频分复用系统的仿真_

基于MATLAB的频分复用系统的仿真_毕业论文(设计)

Abstract

With the development of communication technologyFrequency - Division Multiplexing technology in a wide range of applications and mobile communicationsFrequency - division multiplexing is to the total bandwidth of the transmission channel Transmission channel is divided into a number of child channels each of the transmission signal all the wayEach channel occupies a different frequency and less than the total bandwidth of a channel frequency Each Channel separates each other at the same time mutual interference to improve bandwidth utilizationIt less than ideal and channel noise interference filter characteristics

MATLAB technology to nonlinear dynamic system modeling and simulation Its Provides solutions for scientific research and the design of numerical calculation

The design of frequency division multiplexing system using MATLAB Technology Design and Simulation Through the acquisition of signals by using band - pass filter and low - pass filter spectrum It deepen the understanding of FDMA communication technology and mastering

Key words MATLAB technology frequency division multiplexing technology channel frequency band simulation

目 录

摘 要I

AbstractII

1 引言1

2FDMA的设计原理及过程1

21频分复用的原理1

22模型的建立2

23信号的采样4

24调制语音信号5

25系统的滤波器设计6

26信道的噪声分析7

3MATLAB的仿真8

31语音信号的仿真8

32仿真复用信号的频谱9

33仿真传输信号10

34仿真解调信号10

35仿真信号恢复后的时域和频域11

总结13

致谢14

参考文献15

附录16

1 引言

依据频分复用的复用的原理运用MATLAB软件采集两路以上的语音信号通过合适的高频载波调制然后设计必要的带通滤波器和低通滤波器把得到的复用信号恢复成所采样的语音信号在整个设计过程中运用MATLAB进行仿真对采样的语音信号进行频域和时域的分析通过本次设计可以加深我们对FDMA系统的认识和掌握学会对信道噪声的干扰进行分析和消除同时学会MATLAB软件的基本使用及对软件的设计和仿真掌握低通和带通滤波器的设计

2FDMA的设计原理及过程

21频分复用的原理

频分复用通信系统的核心思想是频分复用复用是将彼此独立的若干个信号合并为一个复合信号而这个信号可在同一个信道上传送复用也就是在一条信道上同时传输几路信号以提高资源[2]

频分复用是将信号资源划分为多个子频带每个子频带占用不同的频率然后把多个信号的频谱调到不同的频带上在一个信道上如下图所示

图 1 频分复用的子频带划分

22模型的建立

频谱的搬移是频分复用的关键技术而其是以混频而实现的下图为频谱的原理图

图 2 混频原理

由上图可知混频的时域表达

[2] 1

混频的双边带频谱图结构如下图所示

图 3 双边带频谱结构

图示可知上边带是从低频到高频分量和基带频率分量一致上边带可以