摘 要
下一代超宽带无线通信技术可能会采用毫米波段的通信频率，毫米波光纤无线系统能够提供高速的宽带服务，同时还解决了频率资源短缺的问题。毫米波通信系统与传统无线系统相比有很多优点，但是毫米波在大气中衰减很快，为了实现大面积通信就必须有更多的基站，这无疑会导致系统成本大幅度上升。光纤无线系统能避免长距离传送毫米波产生的衰减问题，将系统的主要功能集中到少数的中心站，而基站的结构则尽量简化。大学论文网www.wnwu.com
本论文的主要内容是在相位调制器与马赫-曾德尔干涉仪组成的ROF系统中如何利用光学倍频法产生40GHZ的光毫米波信号。其原理是：在基站中配置梳状滤波器，同时在中心站产生一个扫频的光信号，基站利用梳状滤波器频率响应周期起伏特性，将频率变化的光信号转变成强度变化的光信号，然后通过光探测器拍频得到多倍频毫米波信号。本论文用Optisystem 仿真软件对所设计的光学倍频系统进行了仿真，成功地将基站收到的信号的奇数边带与偶数边带进行了分离，并在光电探测器拍频后产生了一个40GHZ的毫米波信号，仿真的结果与理论分析的结果符合得很好。
关键词：光纤无线系统，毫米波，光学倍频法，马赫-曾德尔干涉仪，大学论文网www.wnwu.com
Optisystem 仿真
ABSTRACT
The next generation of ultra-wideband wireless communications technology may be the use of mm-band communication frequencies. Millimeter-wave radio over fiber system can provide high-speed wireless broadband services, but also solved the problem of shortage of frequency resources. Millimeter-wave communication system compared to traditional wireless systems have many advantages, but millimeter-wave attenuation in the atmosphere very quickly. In order to achieve a large area of communication there must be more base stations, which will undoubtedly result in a significant increase in system cost. Optical wireless system can avoid long-distance transmission of millimeter wave attenuation. The system will be focused on core functions of the system to the center of a small number of stations, and the structure of the base station is as simple as possible.
The main contents of this paper how to use optical frequency doubling method to generate optical millimeter-wave signal 40GHZ in phase modulator with Mach - Zehnder interferometer consisting of ROF system. The principle is: In the base station configure comb filter, while center station generate the optical frequency sweep signal. The base station transform frequency change of optical signal into intensity changes of optical signal by using the frequency response of comb filter characteristic cycle ups and downs, and then we can get the octave-band millimeter-wave signal after the photodetector. We simulate Optical Multi-frequency system which is we designed using Optisystem simulation software. The base station successfully received signals and even-numbered and odd-numbered were isolated, and after photodetector beat a 40GHZ millimeter-wave signal is generated. The simulation results with our theoretical analysis are in good agreement with the results.大学论文网www.wnwu.com
Keywords: Radio over Fiber, Millimeter-wave, Optical Frequency Multiplication, Mach-Zehnder Interferometer, Optisystem simulation
目 录
第一章 绪论 1
1.1引言 1
1.2光纤无线通信系统概述 3
1.2.1 ROF系统的基本结构 3
1.2.2 ROF通信技术的特点 4
1.2.3 ROF技术在通信系统中的应用 5
1.3 ROF通信的国内外研究进展 6
第二章 光学倍频系统的原理分析 7
2.1光学倍频法基本思想 7
2.2扫频光波大学论文网www.wnwu.com 7
2.2.1扫频光波的概念 7
2.2.2扫频光信号的产生 9
2.2.3几种常用的扫频波形 10
2.2.3.1三角波扫频 10
2.2.3.2锯齿波扫频 11
2.2.3.3正弦波扫频 11
2.3光纤M-Z干涉仪型Interleaver 12
2.3.1引言 12
2.3.2光纤Mach-Zehnder干涉仪原理 13
2.3.3 MZI型光纤Interleaver原理 15
2.3.3.1 Interleaver原理 15
2.3.3.2基于 MZI型全光纤Interleaver原理 16
2.4光学倍频系统研究现状 18
第三章 基于相位调制器和MZI的多倍频毫米波产生系统 19
3.1系统原理 19
3.1.1 毫米载波的产生 19
3.1.2基带信号的调制的传输 21
3.2系统仿真实验大学论文网www.wnwu.com 24
3.2.1 Optisystem 简介 24
3.2.2实验装置及原理图 24
3.2.3模块分析 25
3.2.3.1中心站 25
3.2.3.2基站 26
3.3实验结果及分析 27
3.4不同传输距离、光电探测器接MZI的不同输出端口时的眼图比较 35
3.5如何看眼图 37
结论 40
参考文献 41
致谢 43
