说明：  本程序包含在高斯噪声信道下QPSK的性能仿真 并且对QPSK进行了频谱分析 比较了调制前 调制后 以及经过噪声后的频谱关系
(This procedure is included in the Gaussian noise channel QPSK performance simulation and spectrum analysis carried out on the QPSK modulation compared before and after the modulated noise spectrum after the relationship)