结合SLMSST和DO提取时变结构瞬时频率OA北大核心CSTPCD

In order to improve the accuracy of instantaneous frequency identified by local maximum synchrosqueezing transform,a new algorithm is proposed by combining second order local maximum synchrosqueezing transform(SLMSST)and dynamic optimization(DO).In this method,the second order phase and amplitude are introduced at first to obtain more accurate second order instantaneous frequency positions.Then,the local maximum values of the time-frequency coefficients are searched in the frequency direction and the corresponding positions of the second order frequencies are found.According to these positions,the time-frequency coefficients are reassigned to obtain the instantaneous frequency band by the SLMSST.Finally,the dynamic optimization method is applied to extract the instantaneous frequency curve inside the frequency band.A numerical case and a test on a time-varying cable are investigated to verify the effectiveness of the proposed method.The results demonstrate that the proposed method behaves better than local maximum synchrosqueezing transform.It not only enhances the accuracy of instantaneous frequency identification,but also has better time-frequency energy concentration.