基于双锁相环路的非正弦时域正交调制外同步方法

针对非正弦时域正交调制信号难以同步的问题,从该调制信号的时域并行、频谱交叠特性入手,提出了一种基于双锁相环路的外同步方法。该方法使用与调制信号频域分离的带通PSWF脉冲序列作为辅助同步序列。接收端同步捕获时,首先利用窄带锁相环完成载波同步,在此基础上,通过相干解调得到基带PSWF脉冲序列,最后通过数字脉冲锁相环实现码元同步。仿真结果表明,该方法具有同步捕获快、稳定性好、抗噪声能力强的优点,尤其适用于并行调制路数较多的情况。

External synchronization method based on double PLLs for nonsinusoidal orthogonal modulation in time domain

To accomplish the synchronization of nonsinusoidal orthogonal modulated signals,an external synchronization method based on double Phase-Locked Loops(PLLs) is proposed.An auxiliary sequence made up of bandpass Prolate Spheroidal Wave Function(PSWF) pulses is used in the method.The auxiliary sequence is separated from the modulated signals in the frequency domain.In the synchronization procedure,the carrier synchronization is first achieved by the narrowband PLLs.Then on this basis the baseband PSWF sequence is obtained by the coherent demodulation.Finally,the digital pulse PLLs is employed to achieve the symbol synchronization.Simulation results show that the proposed method can accomplish the synchronization quickly,and it has good robustness and strong ability to overcome noise.In particular,the method is applicable to the system,which has many parallel modulated subbands.