基于FPGA的改进QAM载波同步算法的研究与实现

Research and Implementation of Improved QAM Carrier Synchronization Algorithm Based on FPGA

对常用的载波同步算法进行分析比较,从频偏捕获能力和相位稳定两方面考虑,提出一种运用正交振幅调制(QAM)系统的联合载波同步算法。运用硬件描述语言Verilog HDL和调用IP核实现各功能模块,采用自顶向下的系统设计思想,在现场可编程门阵列(FPGA)平台上实现了极性判决算法、面向判决算法和优化算法的功能,利用MATLAB对解调恢复的基带信号形成星座图,验证了该优化算法能够较大程度地提升QAM系统的解调性能。

The common carrier synchronization algorithms were analyzed and compared,and a joint carrier synchronization algorithm applied to quadrature amplitude modulation(QAM)system was proposed from two aspects of frequency offset capture capability and phase stability.Hardware description language Verilog HDL and calling IP core were used to realize each functional module.The top-down system design idea was adopted to realize the functions of polarity decision algorithm,decision directed algorithm and optimization algorithm on the field programmable gate array(FPGA)platform.The constellation diagram was formed by using MATLAB to demodulate the recovered baseband signal,which proved that the optimization algorithm can greatly improve the demodulation performance of QAM system.