摘要
在国际移动卫星通信系统中,由于多普勒效应,无线电信号会产生频率偏移现象,卫星执行频率转换时也会产生误差,这样会对射频通信系统接收性能和频带资源利用产生很大的影响,如果不对频率进行修正,将极大地限制系统的应用范围。简要介绍了自动频率控制系统的基本原理,进而分析了基于国际移动卫星通信系统的自动频率控制的方式及其算法;通过预测的频偏值与固有谐振频率匹配,可以补偿和调节地面站上变频器和下变频器输出的载波频率。
In Inmarsat satellite communieation system, the Doppler frequency drift and the frequency error in satellite conversion have negative impacts on RF receive performance and the use of the frequency resource in RF signal transmission process; with no frequency correction, the application of RF system will be greatly restricted. This paper introduces the basic principle of automatic frequency control system;analyzes the AFC method and algorithm based on Inmarsat satellite communication system; by the matching of pre-estimated offset value and the inherent resonance frequency, the carrier frequencies output by the up and down frequency converters at earth station may be compensated and adjusted.
出处
《无线电通信技术》
2011年第1期10-12,33,共4页
Radio Communications Technology
