信号BPSK源程序，滚降系数分别为为0.4，0.7，1.0 信噪比为20dB，自己编的-BPSK signal source, roll-off coefficient 0.4,0.7,1.0 respectively for SNR 20dB, own the

数字通信系统模拟，AWGN，给定不同的SNR，测试BPSK 4PAM 8PAM抗噪声能力。-Digital communication system simulation, AWGN, given the different SNR, test BPSK 4PAM 8PAM noise immunity.