Waters 2998, Обзор и руководство по обслуживанию

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December 5, 2017, 715004753 Rev. B
Page 67
5.4.4 Threshold angle
In addition to computing spectral contrast angles, the spectral contrast algorithm also computes a
threshold angle. The threshold angle is the maximum spectral contrast angle between spectra that
can be attributed to nonideal phenomena.
Comparison of a spectral contrast angle to its threshold angle can help determine whether the
shape difference between spectra is significant. In general, a spectral contrast angle less than its
threshold angle indicates that shape differences are attributable to nonideal phenomena alone and
that no evidence exists for significant differences between the spectra. A spectral contrast angle
greater than its threshold angle indicates that the shape differences arise from significant
differences between the spectra. When automating the spectral contrast comparison, the
maximum absorbance of the spectra must not exceed 1 AU.