中文说明：在通信系统中要搭建一个简单的基带传输系统，此代码正是基于QPSK的基带传输系统，包括编码模块，调制模块，解调模块，译码模块等。
English Description：
In the communication system to build a simple baseband transmission system, this code is based on QPSK baseband transmission system comprising an encoding module, the modulation module, demodulation module, decoding module.