减少多普勒信号时频分布斑点的研究

A new study on speckle reduction of Doppler signal spectra

商用多普勒分析仪应用短时傅立叶变换(STFT)对多普勒信号进行分析,其所得出的信号时频分布图上存在较多的多普勒斑点;为了减少或抑制这些多普勒斑点,得出较精确的医用参数或指标,讨论了一种基于维纳辛钦定理加窗函数对多普勒信号进行分析的新方法,并将分析结果与STFT法做了对比;最终,我们发现应用这种新方法能有效地减少多普勒斑点,得到更光滑精确的信号时频分布图.

There always exists Doppler speckle in the Doppler signal time-frequency representation obtained from short-time Fourier transform (STFT) based commercial analyzers.In the present study,a new method based on Wiener-khintchine theorem and window function was used to reduce Doppler speckle.Time-frequency representation computed using this new method was compared with those computed using the STFT,and the final results showed that this new method has the better performance on reducing Doppler speckle and can generate a more accurate time-frequency representation.