说明：  加性高斯白噪声信道的仿真。利用BOX-MULLER算法产生信道，画出PDF曲线。采用基于CDF的K-S TEST来检测所产生的高斯信道是否符合理论分布。
(Additive white Gaussian noise channel emulation. BOX-MULLER algorithm to generate the channel, to draw PDF curve. Based on the CDF of KS the TEST to detect the generated Gaussian channel is the theoretical distribution.)