基于时频分析的多项式相位信号瞬时频率估计
首先，本文在介绍了多项式相位信号研究背景的基础上，引出了短时傅立叶变换、Wigner-Ville分布以及S-Method等几种常用的时频分布的基本理论和性质，并从交叉项干扰和时频聚集性两方面对这几种分布做了比较。之后，本文着重介绍了复延迟时频分布。从加强时频聚集性和抑制交叉项两方面考虑，介绍了复延迟分布的改进方案，即基于模糊域实现的复延迟时频分布和L型复延迟时频分布。基于上述分析，运用MATLAB仿真分析了不同方法的估计性能。通过仿真分析得出，对于复杂的快变信号，复延迟时频分布具有较好的性能，其时频聚集性高，交叉项影响小，具有广阔的应用前景。关键词 多项式相位信号 时频分析 瞬时频率 复延迟参数8625
毕业设计说明书（论文）外文摘要
Title Estimating the instantaneous frequency of a polynomial phase signal using time-frequency distributions
Abstract
PPS( Polynomial Phase Signal) is a class of non-stationary signals that have been applied in the wide fields, and the traditional time domain and frequency domain analysis methods can’t represent characteristics of the signal comprehensively. But the time-frequency distribution provides a effective way to study the non-stationary signals, and this method is applied to estimate the instantaneous frequency of the polynomial phase signal in the paper.
Firstly, the paper introduces the research background of PPS, and lists some time-frequency distributions, such as short time Fourier transform, the Wigner-Ville distribution and S-Method, and the cross-term interference and time-frequency concentration between different distributions are compared. Then the paper emphasized on the time-frequency distribution with complex-lag, and improved CTD methods are introduced. Based on the theoretical analysis, all these time-frequency distribution methods are implemented with Matlab , and simulation results are given. The results show that CTD is suitable for analyzing the signals with highly non-stationary instantaneous frequency, and its excellences of high time-frequency concentration and less cross-term interference make a promise of wide applications in the future.
Keywords polynomial-phase signal, time-frequency analysis, instantaneous frequency estimation, complex-lag argument
目 录
1 绪论 1
1.1 研究的背景和意义 1
1.2 国内外研究动态 1
1.3 本文的主要工作 3
2 时频分析基本理论 5
2.1 时频分析的基本概念 5
2.2 线性时频变换 7
2.3 双线性时频表示 10
2.4 S-Method 15
2.5 时频分布性能比较 18
3 复延迟型时频分布 21
3.1 复延迟型时频分布 21
3.2 基于模糊域实现的复延迟型时频分布 28
3.3 L型复延迟时频分布 30
4 多项式相位信号瞬时频率估计 34
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