比值校正法在射电频谱中的应用  

The Application of Ratio Correction in Radio Spectrum

作　　者：张燕坤 董亮[1] 李明悦 何乐生[3] 汪敏[1] Zhang Yankun;Dong Liang;Li Mingyue;He Lesheng;Wang Min(Yunnan Observatories,Chinese Academy of Sciences,Kunming 650216,China;University of Chinese Academic of Sciences,Beijing 100049,China;School of Information,Yunnan University,Kunming 650504,China)

机构地区：[1]中国科学院云南天文台,云南昆明650216 [2]中国科学院大学,北京100049 [3]云南大学信息学院,云南昆明650504

出　　处：《天文研究与技术》2020年第3期283-291,共9页Astronomical Research & Technology

基　　金：国家自然科学基金(U1631121,11903079,11903080,11941003);云南省应用基础研究计划面上项目(2019FB009)资助。

摘　　要：分子谱线可以在射电频谱上显现,但是采用离散数字功率谱分析算法会引入离散误差,难以获得分子谱线准确的频谱信息。针对射电频谱上离散数字功率谱分析带来的频率偏移问题进行比值校正法研究,该方法是频谱校正方法的一种,特点在于算法简单,方便快捷。利用射频信号相同、分辨率不同和射频信号不同、分辨率不同情况下,归一化频率偏移量的变化确定该方法的校正效果,最终实现了射频为80.0 MHz,141.8 MHz和270.8 MHz的频谱校正,将相应的频谱分辨率提高到7.5 Hz/channel。通过实验结果对比,确定了测试系统的最佳频率分辨率为50 Hz/Channel或200 Hz/channel。Molecular spectral lines can be viewed on the radio spectrum,but discrete digital power spectrum analysis algorithms would introduce errors that make it difficult to obtain accurate information about spectral lines.In this paper,we study the ratio correction method and carry it out to solve the problem of frequency offset in discrete digital power spectrum analysis.This method is a kind of spectrum correction method,which is characterized by simple,convenient and fast algorithm.The correction effect of this method is determined by the change of the normalized frequency offset under the condition of the same radio signals with different spectral resolution,or different radio signals with different spectral resolution.We finally complete the correction in tests of setting the radio frequency to be 80.0 MHz,141.8 MHz and 270.8 MHz,and improve the frequency resolution to 7.5 Hz/channel.By comparing the experimental results,the optimal frequency resolution of the sampling system is determined to be 50.0 Hz/channel and 200.0 Hz/channel.

关 键 词：离散频谱分析 比值校正法 谱线 频谱分辨率 

分 类 号：TN911.7[电子电信—通信与信息系统]