根据毫米波目标辐射信号小波变换的特征，使用非负小波系数作信号的小波系数，对于确定的阈值，令小于阈值的小波系数为零，大于阈值的小波系数减去常数a ，利用信号的方差函数推导了a 的取值方 法，实验表明该方法有良好的去除毫米波目标辐射信号噪声的能力

In this paper based on the characteristics of millimeter wave radiation signal for wavelet transform, non-negative wavelet coefficient is used as the wavelet coefficient of the signal. For a given threshold value, the wavelet coefficient which is smaller than the threshold is set zero and the wavelet coefficient which is larger than the threshold is set the difference between the coefficient and a constant a.The method for valuing a is inferred by the variance function of signal, and the experiments show that it has good ability of removing the noise in MMW target radiation signal.