本代码为matlab编写，编程实现信号经过QPSK调制后，再经过AWGN信道下，得到的误码率性能曲线，并且与理论上的误码率进行对比。-The matlab code is written in programming through the QPSK modulation signal, and then through the AWGN channel, the resulting bit error rate performance curve, and with the theoretic