Research On Signal Detection And Parameter Estimation Based On Time Frequency Analysis

In stationary signal analysis,time and frequency are two very important variables,Fourier transform and its inverse transform to establish a mapping between the signal in the frequency domain and time domain.Frequency distribution based on the Fourier transformed signal and the energy of the frequency domain representation of the signal reveals the characteristic frequency domain,but the Fourier transform is a overall transform,the characterization of the signal in time domain is either completely,or entirely in the frequency domain,which can not analyze the signal frequency changes with time.For non-stationary signals,Fourier transform can not conduct a comprehensive analysis,in order to understand their frequency relationships change over time,frequency analysis methods is necessary.Now,Time-Frequency Analysis is one of the top interests in Signal Processing,and more and more research has been put on this topic.As one of the best tools to analyze the non-stationary signals,it shows a good picture in the jont time-frequency domain and makes us know about the change of frequency along with the time clearly.Typical non-stationary signals,which is characterized by a limited duration,and is time-varying.Joint time-frequency analysis is focused on variable spectral features of this constituent when the true signal.To reveal the number of frequency components,and each component is contained in the signal over time to change.In many situation,signal often right and wrong steady,its statistics is the time-variable function,the convention Fourier transformation method cannot portray any time the frequency component,is unable to carry on the comprehensive analysis to it.When the frequency analysis method transforms the unidimensional time domain signal to the two-dimensional time domain plane,comprehensive reflection signal time frequency union characteristic.This article introduced the short-time Fourier transformation,the continual wavelet transformation,Wigner-Ville distribute three time frequency analysis method,through the theory composite signal pilot calculation,carries on to several kind of commonly used signals when the frequency analysis,through the simulation chart,the characteristic parameter carries on the recognition computation to the signal arteries in,thus achieves the signal identification the goal.