PLL_Design_3_costas

代码说明：

  该程序利用三阶科斯塔斯环实现锁相环结构，有效的估计输入信号的相位变化，在通信系统的同步上广泛应用。(The program uses the third-order Costas loop to achieve phase-locked loop structure, effectively estimate the phase change of the input signal, widely used in synchronous communications system.)