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

利用窗函数法设计FIR滤波器，绘制出滤波器的特性图。利用所设计的滤波器对多个频带叠加的正弦信号进行处理，对比滤波前后的信号时域和频域图，验证滤波器的效果。最后录制或下载一段语音信号，对其进行采样和加噪，然后用设计滤波器对加噪后信号进行滤波，绘制出信号的时域波形和频谱，分别计算均值、方差、自相关函数、功率谱，并对滤波前后的信号进行对比。(Using window function design FIR filter, draw the filter characteristic diagram.

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