分别画两个频率不同的正弦信号及他们叠加的信号,y1、y2及他们的叠加信号进行采样,进行傅里叶变换,幅频图,频谱图-Videos two sinusoidal signals of different frequencies, and their superimposed signal, Y1, Y2 and their superimposed signal to be sampled, the Fourier transform, amplitude and frequency diagram, the spectrum