当M=4时，编写QAM的蒙特卡罗仿真程序，绘出误符号率和误码率曲线，并和理论曲线比较。-When M = 4, the preparation of QAM of the Monte Carlo simulation program, draw the symbol error rate and bit error rate curve, and and the theoretical curves.

完成M=4的正交信号的数字通信系统的蒙特卡罗仿真。分析其在加性高斯白噪声下误码率与信噪比之间的关系，绘出误码率-信噪比曲线图，并和物理曲线进行比较。-The completion of M = 4 orthogonal signals in Monte Carlo simulation of digital communication systems. Analysis of the additive white Gaussian noise bit error rate and signal