Thermonicolet Omnic Software User's Guide 6.1 (PDF) - Charles E ...

Perform arithmetic operations on spectra
1. Select the spectra on which you want to perform the arithmetic.
You can select one or two spectra. Remember to hold down the Control key
when selecting a second spectrum.
The spectra must be in the same spectral window. If they are not, first copy
and paste one of the spectra into the window that contains the other.
2. Choose Spectral Math from the Process menu.
The Spectral Math window appears with the selected spectrum or spectra
displayed in the upper pane or panes. Here is an example:
The title of each spectrum appears in its pane. The spectrum you selected first
appears in the top pane. When you specify the operation, this spectrum is
represented by the constant A. If you selected two spectra, the second
spectrum is represented by the constant B.
Note
If the spectra don’t have the same resolution, the spectrum with the higher resolution
will be temporarily deresolved to match the resolution of the other spectrum. ▲
The spectral region displayed in the window is the same region that was
displayed when you chose Spectral Math. To display a different region of all
the spectra, use the view finder.
3. Select an operation from the Operation drop-down list box or type an
operation in the Operation text box.
If you include the factor k, you can change its value in two ways: by using
the scroll bar to the left of the subtraction result or by typing a new value.
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