通信卫星转发器噪声系数测量的修正方法

摘要

针对现有y因子法无法精确测量镜像抑制非理想通信卫星转发器噪声系数的问题,提出一种测量的修正方法.通过对转发器镜像抑制度的测量,修正y因子法的测量结果,得出更为精确可信的噪声系数测量结果,从而为星地通信链路设计及卫星通信性能的评估提供更加可靠的参考依据.理论推导、仿真分析及实测结果均表明:修正方法在一定程度上规避了y因子法的测量局限性,能大幅提升转发器噪声系数测量的正确性和精确度;而且,被测转发器的镜像抑制度越差,修正方法改善效果越明显,这为整星噪声系数的精确测量提供了一种新的解决思路.%In order to solve the problem that the existing Y factor method can't accurately measure the noise figure of a transponder with unsatisfactory image rejection performance,a correction method is proposed.Based on the measurement of image rejection of the transponder,the measurement result of the Y factor is corrected,therefore the measurement result is more accurate and credible.This measurement result can provide a more reliable reference and basis for the design of the communications link between satellite and the earth as well as the estimate of the satellite communications performance.The theoretical,simulation and experimental results indicate that the correction method avoids the limitation of the Y factor method,and improves the accuracy of the noise figure measurement result.The worse the image rejection is,the more obvious the improvement is.This paper provides a new solution of the accurate measurement of satellite noise figure.