多项式Wigner-Vill分布(PWVD)能很好地对非线性调频信号进行分析。利用PWVD平面上的尖峰值作为非线性调频信号的瞬时频率的估计。在PWVD上,对估计的瞬时频率进行差分,利用信号差分方程的特征,结合直方图统计方法在低信噪比情况中从PWVD平面提取方差很小的瞬时频率点,从而达到精确估计的目的。 Polynomial Wigner-Vill distribution (PWVD) is a good way to analyze nonlinear FM signals. The spike on the PWVD plane is used as an estimate of the instantaneous frequency of the nonlinear FM signal. In PWVD, the estimated instantaneous frequency is differentiated, and the feature of signal difference equation is used in combination with the histogram statistics method to extract the instantaneous frequency point with a small variance from the PWVD plane in the case of low signal-to-noise ratio, so as to achieve the accurate estimation.