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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.