摘要
针对卫星通信中常用的多进制相移键控调制(MPSK)信号,在无导频数据且不考虑编码辅助条件下,对一种低信噪比、大频偏的联合载波频率估计方法进行了研究。将FFT频谱细化方法与Fitz法进行联合设计并优化,先用FFT频偏估计细化算法粗略估计频偏,使之处于Fitz的范围内,再用Fitz法对经一次补偿的信号进行精细估计,将二次补偿后的信号送二阶锁相环路实现载波同步,并对频偏补偿环路在低信噪比下的稳定性进行设计和优化,给出了优化流程。在Matlab/Simulink仿真平台上对8PSK信号进行仿真,验证了算法可实现在宽带范围内8PSK调制信号的载波频率同步,且同步门限降至6dB。
For high order MPSK signal in satellite telecommunication,a united estimation method of carrier frequency with low signal to noise ratio and large frequency shift without data aided was studied in this paper.The FFT spectral fining and Fitz method were designed jointly and optimization were applied.The frequency shift was estimated roughly by FFT to enter into Fitz range,and then the signal after first time compensation was estimated finely by Fitz.The signal after the second time compensation was sent to the 2-order phase-locked loop to realize the carrier frequency synchronism.The stability of the frequency drift compensation loop under low signal-noise-ratio was designed and optimazied.The optimal flowchart was given out.The 8 PSK signal was simulated on Matlab/Simulink platform,which proved the algorithm proposed could realize the carrier frequency synchronism of wideband 8 PSK signal and the synchronism threshold could be low to 6 dB.
出处
《上海航天》
CSCD
2017年第5期94-98,共5页
Aerospace Shanghai
基金
高分辨率对地观测重大专项资助(GFZX04013204)
关键词
高阶调制MPSK信号
载波频率同步
锁频环路
同步门限
非数据辅助
低信噪比
大频偏
快速傅里叶变换
Fitz
high order MPSK signal
carrier frequency synchronism
frequency lock loop
synchronization threshold
non-data aided
low signal to noise ra t io
large frequency sh if t
F F T
Fitz method
