利用matlab仿真实现载波的平方环载波同步,costas环载波同步和符号同步.-achieved quadratic loop carrier synchronization, costas loop synchronization and symbol synchronization within matlab

自己用matlab编写的平方锁相环的仿真，对锁相环研究的同学具有很好的参考价值(The simulation of PLL written by myself in MATLAB is of great reference value to the students who study PLL.)