基于改进同步挤压小波变换识别信号瞬时频率

Instantaneous Frequency Identification of Signals Based on Improved Synchrosqueezing Wavelet Transform

提出了改进同步挤压小波变换。首先,采用解析模态分解定理将非平稳响应信号分解为多个单分量信号;其次,通过频率转换将分解后的单分量信号从低频区域转换到高频区域以提高时间分辨率;然后,对频率重点关注区域的时频代表值进行局部挤压,提高时频曲线的频率精度;最后,通过两个数值算例和一个拉索试验验证了改进同步挤压小波变换方法的有效性和准确性。研究结果表明,改进同步挤压小波变换能够提高信号在特定区域内的瞬时频率识别精度,是一种可行的时变结构参数识别方法。

Synchrosqueezing wavelet transform can get better frequency resolution by reassigning the timefrequency representation of wavelet transform.However,the diffusion along frequency domain can be suppressed while the diffusion along the time axis cannot be overcome.To address this issue,an improved synchrosqueezing wavelet transform is employed to enhance the accuracy of estimated instantaneous characteristic parameters in both time and frequency directions where we highly focus on.Two numerical simulations and a cable test with linearly and sinusoidal varying tension forces are used to verify the effectiveness and accuracy of the proposed method.The results demonstrate that the improved synchrosqueezing wavelet transform is appropriate for identifying parameters of time-varying structures with both better time and frequency resolutions in a specific region.