Instantaneous frequency identification based on synchrosqueezing wavelet transform
LIU Jing-liang1,REN Wei-xin 1,2,WANG Zuo-cai2,HU Yi-ding1
1. School of Civil Engineering, Central South University, Changsha 410075, China;2. School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China
Abstract:A continuous and invertible synchrosqueezing wavelet transform is performed on a time-varying response signal and instantaneous frequency can be accurately identified as a result. The effectiveness and accuracy of the proposed method is validated via classical Duffing system and a numerical example of two-story shear building with two kinds of force vibration. Finally, a cable structure test is set up with linear and sinusoidal varying tensions respectively applied to the cable, which result in time-varying and nonlinear stiffness. Among three mother wavelet function, complex Morlet synchrosqueezing wavelet transform algorithm is introduced for instantaneous frequency identification. The results of numerical simulations and experimental test demonstrate that the method can extract the instantaneous frequency effectively and the choosing of mother wavelet function has little effect on instantaneous frequency identification.