QAM源代码，方便大家使用，谢谢分享，其实我也有点无奈-QAM source code, easy to use you, thank you sharing, in fact, I feel quite helpless

OFMD系统包含8个子载波，f=1Hz，子载波频率间隔为1Hz，每个子载波4-QAM，符号周期1s(The OFMD system contains 8 sub-carriers, f = 1 Hz, sub-carrier frequency interval is 1 Hz, 4-QAM per sub-carrier, symbol period 1s)