OFDM完美出图，信噪比，16QAM星座图，加窗信号时域和频域波形图-Perfect figure, OFDM SNR, 16 qam constellation diagram, add window signal time domain and frequency domain waveform figure

进行纯净信号和加噪信号的时频域显示，及其包络图显示，并计算加噪信号的信噪比、互相关系数、峭度值，对信号进行离散余弦变换。(The time-frequency domain display of pure signal and noise-added signal and its envelope diagram display are carried out, and the signal-to-noise ratio, correlation coefficient and kurtosis