无线电工程

载波同步和均衡是正交幅度调制(QAM)解调器中的2个重要组成部分。提出了一种适用于QAM信号的载波同步与自适应均衡的联合结构,载波同步采用通用环,均衡器采用基于CMA和LMS算法的DFE结构。使用CMA算法进行初步收敛,载波同步后,均衡器转到LMS算法,保证了良好的稳态跟踪性能。通过对算法的简化,减少了硬件资源。该方案载波捕获范围超过40 kHz,完全满足侦察接收机的需要。

Carrier synchronization and equalization are two important parts in QAM demodulator.In this paper,a joint design and implementation of carrier synchronization and equalization is presented.A universal carrier recovery loop is used to correct the frequency offset.The equalizer has been designed using CMA and LMS algorithm,combined with a DFE structure.Through simplifying the algorithm,the hardware resource is decreased.Simulation results indicate that the design has better stability and good tracking capability and can capture frequency offset of more than 40kHz.It can completely satisfy the requirements of reconnaissance receiver.