Nonstationary harmonic signal extraction from strong chaotic interference based on synchrosqueezed wavelet transform

To overcome the shortcomings of the synchrosqueezed wavelet transform (SWT) in extracting nonstationary harmonic signals from chaotic backgrounds, an improved nonstationary extraction method with SWT is proposed based on an adaptive optimal accumulation frequency range. First, according to the relationship between the wavelet coefficients of the nonstationary harmonic signals and the support interval of the mother wavelet function, an adaptive accumulation frequency range formula is derived for extracting the nonstationary harmonic signal. Then, the optimal value of the parameter of the adaptive accumulation frequency range formula is determined using the minimum energy error criterion to realize the adaptive SWT extraction of nonstationary harmonic signals. In experiments, various types of nonstationary harmonic signals are extracted from the Lorenz background and Duffing background using both a classic SWT method and the proposed method. The experimental results show that the proposed method can effectively extract nonstationary harmonic signals from noisy backgrounds. Compared with the classical SWT method, the mean square error of the extracted harmonic signal by the proposed method is lower, and the correlation coefficient is higher.