说明：  alpha=0时基带信号眼图。同理，想得到不同alpha值时的眼图，只要把对应的程序段中的alpha改为你想要的即可。
(alpha = 0 time-base-band signal eye diagram. Similarly, want a different alpha value of the eye diagram, so long as the corresponding program segment of the alpha can be changed to what you want.)