说明：  QAM调制的ＭＡＴＬＡＢ程序仿真，思路清晰，既可以学习如何用ＭＡＴＬＡＢ编程，又可以理解通信调制技术！
(QAM MATLAB simulation procedures, clear thinking, can learn how to use MATLAB programming, but also to understand communication modulation technology!)