文档介绍：线性调频信号的时频分析研究
摘要
线性调频信号是其中一类有代表性的非平稳信号,该信号广泛存在于雷达、声纳、语音、地球物理和生物医学信号处理中。对于这类频率随时间变化的信号,传统的时间域和频率域的分析方法都不能够全面的反映信号的特征,而时频分析是分析和处理非平稳信号的有力工具。利用时频分布,可以对各种信号进行分析、处理,提取信号在特定时间特定频率所具有的特征信息。
文中介绍了线性调频信号的定义及特性,描述了短时傅里叶变换,Wigner—Ville分布,Wigner—Hough分布三种时频分析方法。通过对时频分析方法的原理介绍,运用MATLAB 中的工具箱,对一个线性调频信号进行时频分析的MATLAB仿真。通过对几种时频分析方法比对分析和基于MATLAB信号降噪的仿真实验,验证几种分析方法的优越性。
关键词:线性调频信号时频分析短时Chirp-Fourier变换 Wigner—Ville分布
Wigner—Hough分布
Linear FM signal time-frequency analysis
Abstract
In modern signal processing, linear frequency modulation signal is one representative of non-stationary signals, the signal is widespread in radar, sonar, speech, and geophysics, and biomedical signal processing. Such frequency time-varying signal, the traditional time domain and frequency domain analysis methods are not able to fully reflect the characteristics of the signal, but when the frequency analysis is a powerful tool for analysis and processing of non-stationary signals. Using time-frequency distribution to analyze a variety of signal processing, extract the signal characteristics with a specific frequency at a specific time.
This paper introduces the definition and characteristics of the linear FM signal, describes the short-term Chirp-Fourier Transform, Gabor distribution ,Wigner-Ville distribution of two kinds of time-frequency analysis. By the principle of time-frequency analysis method, the use of the toolbox in MATLAB, MATLAB simulation of time-frequency analysis of a linear FM signal. By frequency analysis of several methods of analysis and MATLAB-based signal to noise simulation and validation of several advantages of the method.
Key words: LFM signal Time-frequency analysis Wigner-Ville distribution Discrete Chirp-Fourier transform
目录
1 绪论 1
课题背景及研究意义 1
国内外发展状况 3
4
2 线性调频信号 5
线性调频信号的定义 5
5
线性调频信号的仿真 6
3 线性调频信号的时频分析方法研究 10
10
10
时频分析方法的介绍和仿真 10
短时傅里叶变换 10
Winger—Ville分布变换结果 16
W-H变