Instantaneous Frequency Estimation Based On Synchrosqueezing S-transform

The instantaneous frequency Estimation is a significant measure for non-stationary signal analysis and processing.Obtaining high precision estimation of instantaneous frequency can extract practical information,and provides priori knowledge such as phase scheme for post processing.As one significant method,time-frequency can obtain signal's time varying details without given priori information,which is an important and efficient tool for non-stationary signal analyzing.Therefore,in this thesis,S-transform is used as the main time-frequency analyzing tool,combined with Synchrosqueezed transform to establish high time-frequency resolution,in order to acquire high precision instantaneous frequency estimation especially in low SNR situation.The entire innovative results in this essay are listed below: 1.Aiming at signal detection in white Gaussian noise background,the statistic model is proposed,which supported by a mathematical derivation of the output of S-transform with pure white Gaussian noise input via.On this bases,a signal detection method of S-transform is proposed achieving detect signal in low SNR circumstances.2.Based on the sensitivity of S-transform towards suddenly changing of the signal phase,a phase hopping detection method and hopping phase estimation method are proposed with detailed derivation and simulation proves.The forward method can reutilize the S transform spectrum with phase jump interference.After detecting the phase jump,the jump phase angle can be estimated quickly.3.Aiming at the requirements of multi-component signal processing,a Focus S-Transform has been proposed,which has good noise suppression ability,high time-frequency resolution and accurate instantaneous frequency estimation.The Focus S-transform is proposed with good adaptation towards different FM signals.The local frequency modulation peculiarity can obtain a better estimation.4.Aiming at the mass time consuming of parameter optimization in Focus S-transform,the Adaptive S-transform is proposed simplifying the mount of parameters in window function.The Adaptive S-transform own the ability to guarantee noise suppression performance,time-frequency resolution,and precision of instantaneous frequency estimation precision.Besides,the inverse of Adaptive S-transform can be achieved simply by integration through frequency axis.This make Adaptive S-transform possess a good interface towards Synchrosqueezed Transforms.5.Aiming at improving the instantaneous frequency estimation of multi-component signals,a Synchrosqueezed Adaptive S-transform,SST-AST,is proposed.This method is under the premise that the signal component does not overlap with the instantaneous frequency.Cascading AST with high order Synchrosqueezed Transform,the spectrum of signal has been broaden by windowing can be reduction to the position of instantaneous frequency.