中文说明：
本程序是用matlab程序语言编写的costas环仿真程序，并对于模拟的costas环的性能进行了分析，costas环主要用于载波同步，本设计实现了对于载波频率跟踪的实现，并且给出图形对比。
English Description：
This program is a Costas loop simulation program written in MATLAB programming language, and analyzes the performance of the simulated Costas loop. Costas loop is mainly used for carrier synchronization. This design realizes the realization of carrier frequency tracking, and gives the graphic comparison.