摘要OFDM（Orthogonal Frequency Division Multiplexing）信号采用正交的多载波概念，相较于传统的单载波信号，具有高的频谱利用率和大的时宽带宽积，非常适用于雷达系统。且这种信号波形的设计非常灵活，不仅保证了信号的距离分辨率，而且面对复杂的电磁环境，有很好的抗干扰能力。 本文主要围绕低 PMEPR 信号的设计展开，首先研究不包含相位编码的传统的 OFDM 信号，分析其数字模型，时、频域正交特性等，然后重点研究降低PMEPR 的方法，包括直接削峰、峰值加窗和峰值抵消，使用 matlab 分别进行了研究和仿真，并得出其各自的优缺点。之后加入相位编码序列，形成 MCPC 大时宽带宽积信号，这种信号应用更为广泛，亦属于 OFDM 信号的一种。针对相同编码序列和循环移位编码序列这两种波形设计方法，通过载波幅度和相位加权降低PMEPR,最后从频谱和自相关函数的角度分析这些方法的性能。  27397 
毕业论文关键词  OFDM，MCPC，matlab 仿真，相位编码，自相关函数，PMEPR
Title   The  Low  PMEPR  Design  Of  OFDM  Radar  Signals               
Abstract OFDM (Orthogonal Frequency Division Multiplxing) signals use the concept of orthogonal multi-carrier .Compared with  the traditional single-carrier signals, they have very high spectrum efficiency and a great time-bandwidth product,and it can be applied to radar systems widely. In addition, this type of method has very flexible waveform design method. Not only can it ensure the distance resolution of the signal, but also  has  a good anti-jamming capability in  the face of complex electromagnetic environment recently. This article is designed around the design of low PMEPR signals. Firstly, it researches the traditional OFDM signals without the phase encoding to analyse  its digital model,the orthogonal property in time and frequency domain and so on. Then,it  focus on  looking for the methods of  reducing PMEPR  that include Clipping,Peak Windowing  and Peak Cancellation. Besides,  many studies  and simulation are  carried  out by matlab to contrast  their  advantages and disadvantages.Secondly,  the phase-encoding sequences are added to this kind of signal,which helps form another sort of signal that has large signal bandwidth product and more general adhibition.And it also belongs to the OFDM signals.For the two waveform design methods  which are the  same coding sequence and cyclic shift coding sequences,amplitude weighting and additional phase angle are used to  drop PMEPR of signals. Finally,we analyze the performance of these methods from the perspective of the spectrum and the autocorrelation function.  Keywords    OFDM， MCPC， matlab  simulation， phase-encoding， autocorrelation function，PMEPR  
目   次
 
1  引言  .  1
1.1 研究背景及意义.  1
1.2 国内外研究现状.  2
1.3 本文主要工作和章节安排.  5
2  基于OFDM 技术的雷达信号    7
2.1 引言.  7
2.2 OFDM 信号的基本原理    7
2.2.1 OFDM 系统结构.  7
2.2.2 OFDM 信号时域结构表现形式.  8
2.2.3 OFDM 信号的数学模型.  9
2.2.4 基于IDFT 的OFDM 实现    10
2.2.5 OFDM 信号正交特性  11
2.2.5.1 OFDM 信号正交性时域验证    11
2.2.5.2 OFDM 信号正交性频域验证    12
2.2.6 OFDM 信号的 matlab 仿真图.  13
2.3 IFFT 点数选择  .  14
2.4 本章小结  17
3  OFDM 雷达信号的峰均比抑制  18 OFDM雷达信号低PMEPR设计:http://www.751com.cn/tongxin/lunwen_21870.html