论文部分内容阅读
文重点研究了QAM调制解调系统接收端实现载波恢复和符号同步的数字方法。所提出的同步解调模型是构建在参数(载波相位和定时)提取的结构之上,全部用数字信号处理技术实现。本文以最大似然估计准则为理论基础,推导出了两种面向判决的载波相位恢复方法(反馈型和Arctan型)和时钟恢复方法,并分别进行了软件仿真和分析。最后提出了载波恢复和定时恢复的联合估计模型。
This paper focuses on the digital method of carrier recovery and symbol synchronization at the receiving end of QAM modem system. The proposed synchronous demodulation model is built on the structure extracted from the parameters (carrier phase and timing), all using digital signal processing techniques. In this paper, based on the maximum likelihood estimation criterion, two decision-oriented carrier phase recovery methods (feedback type and Arctan type) and clock recovery method are deduced, and the software simulation and analysis are respectively carried out. Finally, a joint estimation model of carrier recovery and timing recovery is proposed.