对基带数字通信的位同步过程进行了仿真，采用Gardner算法，没有用插值。符号用SRRC进行脉冲成形，环路滤波器没有用PI回路，是简单的alfa，1-alfa低通滤波，NCO调整也比较简单。-Baseband digital communications for the bit synchronization process of the simulation, using Gardner algorithm, did not use interpolation. Carried out with SRRC pulse shaping symbols, did not use PI loop filter circuit is a simple alfa ,1-alfa low-pass filter, NCO is also relatively simple to adjust.