※ 引述《innevertears (士乎)》之铭言： : 如题 : 今天写考古题的时候，有碰到一题 : 为何有FT-IR但却没有FT-UV/Vis : 参考书上面的答案是写 : 「因为IR的光源弱，属於热侦测器，可用FT的技巧改善S/N ratio : 而UV的光源强，侦测器属於photo type，所以用FT的改善效果不大」 : 後来我自己又去翻了skoog的IR和UV的章节 : 也没有找到相关叙述 : 觉得答案好像少了一些关键点 : 没有解释为何光源强和光源弱改善效果上的差别 : 不知道有没有其他更好的答案，或是这已经是答案了呢? : 先谢谢大家! 我有相同的问题，但是找到答案之後却看不懂，是否有高人可以指点一下？ 每个英文大致看得懂，但合在一起却莫宰羊啊…Q_Q、、 还有，为何光源会闪烁呢？ “Fourier transform instruments are much less common for the ultraviolet, visible and near-infrared region, however, because signal-to-noise limitations for spectral measurements with these types of radiation seldom lies in detector noise but instead in shot noise and flicker noise associated with the source. In contrast to detector noise, the magnitudes of both shot and flicker noise increase as the power of the signal increases. Furthermore, the total noise for all of the resolution elements in a Fourier transform measurement tends to be averaged and spread out uniformly over the entire transformed spectrum. Thus, the signal-to-noise ration for strong peaks in the presence of weak peaks is improved by averaging but degraded for the weaker peaks. For flicker noise, such as is encountered in the background radiation from many spectral sources, degradation of S/N for all peaks is observed. This effect is sometimes termed the multiplex disadvantage and is largely responsible for the fact the Fourier transform has not been widely applied for ultraviolet/visible spectroscopy.”1 --

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