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针对血流多普勒信号的谱估计问题 ,本文将经典的短时傅立叶变换谱图和现代小波尺度图进行了比较 ,从时—频分布的观点出发 ,分析认为STFT谱图和小波尺度图是Wigner-Ville分布的一种特殊形 ,STFT谱图是平滑的伪Wigner -Ville分布 ,小波尺度图是一种仿射平滑的Wigner-Ville分布 ,对于实际仿真的Doppler信号 ,计算得到的STFT谱图和小波尺度图表明 ,小波尺度图的低频效果较好 ,但是交叉项干扰也较大些。
For the spectral estimation of blood flow Doppler signal, this paper compares the classical short-time Fourier transform spectrogram with the modern wavelet scale. From the point of view of time-frequency distribution, we conclude that STFT spectrum and wavelet scale are A special form of Wigner-Ville distribution, the STFT spectrum is a smooth pseudo Wigner-Ville distribution, and the wavelet scale is an affine smoothed Wigner-Ville distribution. For the actually simulated Doppler signal, the calculated STFT spectrum The wavelet scale shows that the low frequency of the wavelet scale is better, but the crosstalk is more disturbing.