中文说明：载波同步是数字通信系统中必不可少的一个环节。BPSK、QPSK 信号是抑制了载波的信号，抑制载波跟踪环包括同相正交环即 costas 环、平方环和判决反馈环。本程序是基本的costas环，是杜勇写的同步技术中的costas环
English Description：
Carrier synchronization is an essential part of digital communication system. BPSK and QPSK signals are carrier suppressed signals. Carrier suppressed tracking loop includes cophase orthogonal loop, namely Costas loop, square loop and decision feedback loop. This program is the basic Costas ring, is written by Du Yong synchronization technology Costas ring