时变AR模型是一种新的时频分析方法, 对简单的非平稳信号瞬时频率的测量具有很高的精度, 但却不适用于复杂信号。为使时变AR模型同样适合于测量复杂信号的瞬时频率, 提出LMD和时变AR模型相结合的方法,该方法使时变AR模型极大地扩展了适用对象。分别采用最小二乘和卡尔曼平滑算法求解信号参数模型, 并求得信号瞬时频率, 仿真对比分析表明,与直接用时变AR模型测量瞬时频率相比, 该改进方法能大大提升瞬时频率测量的准确度。

Time Varying Autoregressive (TVAR) model is a new method for time-frequency analysis,which has high accuracy in instantaneous frequency measurement of simple non-stationary signal.However,it is not applicable to complex signal.In order to make TVAR model also suitable for the measurements of complex signal instantaneous frequency,it is proposed to use Local Mean Decomposition (LMD) together with TVAR model.This method makes the TVAR model greatly expands its scope of application.Least square method and Kalman Smoothing (KS) algorithm are used respectively to solve the signal parameter model,and the instantaneous frequency is obtained.The simulation analysis shows that:Compared with the instantaneous frequency measurement only using TVAR model,the improved method can greatly improve the accuracy.