基于科斯塔斯环法的载波提取的设计

Design of Carrier Synchronization Based on Costas Loop

介绍了平方变换法相干解调原理,从工程角度完善了载波提取的电路结构,消除了频移载波的误锁问题.提出用科斯塔斯环法来实现从2DPSK信号中提取相干载波,解决了提取的载波信号存在180度的相位含糊问题,为通信系统提高抗噪性能提供了条件.当载波频率很高时,工作频率较低的科斯塔斯环易于实现.并用Simulink设计出科斯塔斯环法提取载波的仿真电路图和进行相应的仿真实验.

Theory of coherent demodulation based on method of square counterchange is introduced in this article.The structure of circuit for carrier recovery is perfected in engineering,and the problem of error-lock for frequency-shift carrier is eliminated.Costas Loop is put forward to achieve coherent carrier from 2DPSK signal in this article.The 180° phase＇s inexplicit problem which exist in carrier recovery is resolved.It improves the resisting noise property of communication system.When carrier frequency is higher,Costas loop is easy to implement carrier synchronization.Because the operating frequency of Costas loop is lower than square PLL.We scheme out emulational circuit diagram for carrier distilling with Costas loop by using simulink and process corresponding emulational experiment.