中文说明：
数字喷泉码PPT，主要说明了随机数字喷泉码，LT码，raptor码以及其基本的编译码方法并附加LT coeds的matlab程序。
English Description：
Digital fountain code PPT, mainly describes the random digital fountain code, LT code, raptor code and its basic encoding and decoding methods, and adds LT coeds matlab program.