说明：  说明：不少读者来邮件反映，书中没有COSTAS环的MATALB仿真程序，现将程序发布出来，供大家学习参考，同时也将在《数字通信同步技术的MATALB与FPGA实现》、《数字调制解调技术的MATLAB与FPGA实现》两本书的第2版中添加相关内容（如果有机会再版的话）。
(Explanation: Many readers have emailed to reflect that there is no COSTAS loop MATALB simulation program in the book. Now the program is published for your reference. At the same time, it will be added to the second edition of the two books, MATALB and FPGA implementation of digital communication synchronization technology and MATLAB and FPGA implementation of digital modulation and demodulation technology. (if there's a chance to reprint it).)