说明：  结合调制代码 这个是基于optisystem软件的解调代码。注意修改opti中layout里设定的采样次数 并且matlab输出的矩阵的大小要与opti中的采样次数一致，不然会报错。仔细研究，光纤传输80km是没有问题的。
(Combined with modulation code This is a demodulation code based on optisystem software. Note that the number of sampling times set in the layout in opti is modified and the size of the matrix output by matlab must be consistent with the number of samplings in opti, otherwise an error will be reported. After careful study, it took me almost three weeks to figure it out. Optical fiber transmission of 80km is no problem.)