基于多谱图叠加阈值的抑制WVD交叉项的新方法
A New Method to Suppress Cross-Terms of WVD via Thresholding Superimposition of Multiple Spectrograms
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摘要: 本文提出了一种抑制Wigner-Ville分布(WVD)交叉项的新方法。 首先对多幅具有不同时-频分辨率的谱图进行叠加, 然后对叠加结果进行阈值处理，确定WVD自项在时频平面的支撑区域。 最后，用该区域的示性函数乘以WVD得到一个新的时频分布。 不同于传统的抑制交叉项的核函数方法, 该方法抑制交叉项的同时, 保持WVD了高时频聚集性。 实验结果表明, 该方法对由多个LFM信号构成的多分量信号和非线性调频信号都非常有效。Abstract: In this paper, a new method is proposed to suppress the cross-terms of Wigner-Ville Distribution (WVD), which is based on thresholding the superimposition of multiple spectrograms. First, the spectrograms with different time-frequency resolutions are superimposed and then the superimposition is thresholded to localize the auto-term support region of the WVD. Secondly, the WVD is multiplied by the indication function of the region. In this way, a new Time-Frequency Distribution (TFD) is obtained. Unlike the traditional kernel function methods to suppress cross terms, our method not only reduces the interfering cross-terms but also preserves the superb time-frequency concentration of the WVD. The experimental results show that the method is very effective for both the multicomponent signals consisted of the LFMs and nonlinear frequency modulation chirp signals.
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