说明：  CRC码生成器和卷积码的仿真程序。其中CRC码可以自定义生成多相式或字符串；卷积码可以自定义约束长度和码长。
(CRC code generator and the simulation program convolutional codes. Which the CRC code can customize the generation of multi-phase or string convolutional codes can customize the constraint length and code length.)