建立一个实测信号的样本，这里我建立四个随机信号的样本，因为方便显示，蓝色信号为有用信号（正弦信号），黑色的四个信号是随机信号分别与正弦信号叠加形成的实测信号，最后红色的信号为样本的均值信号，即为时域同步平均效果下的信号。-A sample of the measured signal, I created four random signal samples, because it' s easy to display, blue signal is useful signal (sinusoidal signal), four black signal is a random signal with sinusoidal signal is superimposed on the formation of the measured signal. the final red signal is the mean of the sample signal, that is, the average effect of time-domain synchronous signal.