一种二次相位调制信号的锁相环相干解调算法

A Phase-Locked Loop Coherent Demodulation Algorithm for Twice Phase Modulation Signals

针对二次相位调制信号,设计了一种二次相干解调算法,按顺序依次进行残留载波锁相环相干解调和抑制载波Costas环相干解调,最后经过位同步及判决,得到了原始信息比特。通过对两个环路的鉴相器和滤波器的合理设计,保证了环路的稳定锁定以及信号的可靠传输。该算法适用于远距离低速通信,并可以工作在低信噪比环境中。仿真结果表明,当信噪比为-10dB时,两次解调环路依然能够有效地完成载波同步并正确地进行码元判决,因此有着良好的应用前景。

A twice coherent demodulation algorithm was designed for the twice phase modulations signal, which demodulates residual carrier signal and suppresses carrier signal by phase locked loop and Costas loop coherently and sequentially. Finally, the original information bits were obtained by symbol timing synchronization and decision. The algorithm guarantees the stable lock of the loop and reliable transmission of the signal through the reasonable design of the two phase discriminators and the loop filters. The algorithm is suitable for long distance and low code rate communication and can work in low signal to noise ratio(SNR) environment. The simulation results show that the twice demodulation loops can still complete the task of carrier synchronization and code decision effectively and correctly when SNR is-10 dB. So it will have prospective application potential.