基于时频三参数小波变换的频率衰减梯度分析

Frequency attenuation analysis based on time-frequency three-parameter wavelet transform

为了有效提高常规频率衰减梯度分析法中高频振幅谱的计算精度,提出一种基于时频三参数小波变换的频率衰减梯度分析法。该方法首先利用时频三参数小波变换计算目标信号的时间—频率域振幅谱,再采用非线性曲线拟合法计算高频段振幅谱的频率衰减系数。理论信号分析表明采用时频三参数小波变换的时频分析法提高了短时傅里叶变换的时频分辨率,并克服了常规三参数小波变换出现的能量交叠而引起的高频信号能量衰减假象。实际资料的计算结果表明,本文方法比常规方法具有更高的计算精度和测试吻合率。

In order to improve the calculation accuracy of high frequency amplitude spectrum in the frequency attenuation analysis,this paper proposes a new approach based on time-frequency three-parameter wavelet transform.First we use time-frequency continuous three-parameter wavelet transform to calculate the amplitude spectrum of target signal,and then we calculate the attenuation coefficient of high frequency amplitude spectrum with non-linear algorithm.Theoretical calculation results prove that the proposed approach improves the resolution in both the time and the frequency domains of the short time Fourier transform(STFT),and overcomes the illusion of high frequency signal energy attenuation due to the energy overlap in three-parameter wavelet transform.Real data applications show that our approach has higher accuracy and higher test matching rate than conventional ones.