《现代数字与模拟通信系统》第七章练习，通过这一章的学习可以让学生对眼图，linecoding，M-ary code等A/D方式有更深的了解，代码很简单，但可以很直观理解全过程-" Modern Digital and Analog Communication Systems,"　Chapter VII exercises, learning through this chapter allows students to eye diagram, linecoding, M-ary code and other A/D mode has a deeper understanding of the code is very simple, but it can be very intuitive understand the whole process