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

3. Select the desired number of smooth points from the drop-down list box.
The value to the right of the number of points represents the frequency range
that is considered when smoothing a point in a spectrum. The value is the
product of the number of smooth points and the data spacing of the spectrum.
4. Choose OK.
Smoothing spectra
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The Savitsky-Golay algorithm smoothes all sharp peaks, including sample
peaks. Be careful when smoothing spectra with real spectral absorptions that
are narrow, since these features will also be smoothed.
Smoothing degrades the effective spectral resolution of the data and can
remove (“smooth out”) small spectral features. If possible, collect more scans
instead of smoothing.
Smoothing spectra
automatically
Use Automatic Smooth in the Process menu to improve the appearance of the
selected spectra by automatically smoothing the high-frequency component of the
sample data. Smoothing is useful for improving the appearance of peaks obscured
by noise.
Note
If you want to smooth spectra manually by specifying the degree of smoothing
(setting the number of points), use Smooth. To smooth spectra automatically, use
Automatic Smooth. An automatic smooth often gives a satisfactory result and is
faster than a manual smooth. See “Smoothing spectra” for more information. ▲
Smooth spectra automatically
1. Select the spectra.
2. Choose Automatic Smooth from the Process menu.
Smoothing spectra automatically
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The effects of successive automatic smoothing operations are cumulative:
each time you smooth the same spectrum, the peaks become broader and of
lower intensity.
Be careful when smoothing spectra with real spectral absorptions that are
narrow since these features will also be smoothed.
Changing the data
spacing of spectra
Use Change Data Spacing in the Process menu to change the spacing of the data
points in the selected spectra to a value you select. Data spacing is the number of
wavenumbers between data points in a spectrum. It is determined by the resolution
and zero filling settings used when you collect the spectrum.
If you use this command to change the data spacing of a spectrum to a higher
value, the software deresolves the spectrum. If you change the data spacing of a
spectrum to a lower value, the software zero fills the data; that is, it adds
interpolated data points between the existing data points.
220 Thermo Nicolet