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

Specifying the number
of levels of zero filling
Zero Filling determines the number of levels of zero filling used when the data are
Fourier transformed. Zero filling improves the line shape of a spectrum by adding
data points between collected data points. Sharp features become smoother and
more like typical peaks when zero filling is used.
Because data points are added, the transform takes longer. Zero filling does not
increase the “true” resolution of the data, however, since that is determined by the
number of data points collected.
The available settings of Zero Filling are described in the following table.
Setting
None
Description
No zero filling is done.
1 Level One data point is added between each data point.
2 Levels This setting adds three points between each data point to better
define band shapes.
Set Zero Filling to None for normal work.
Collect your sample and background spectra using the same number of levels of
zero filling.
If band shapes are cut off, set Zero Filling to 1 Level or 2 Levels instead of None.
Selecting the apodization type
The Apodization parameter determines the type of apodization that is used before
the interferogram is Fourier transformed. Apodization removes peak side lobes
that can occur because the interferogram is not an infinite set of data. The
apodization types described in the following table are available. Collect your
sample and background spectra using the same apodization type.
Setting
Happ-Genzel
Triangular
Description
This is the best choice for most applications. It suppresses
side lobes more effectively than the triangular type and with
less reduction in resolution than that type. (It results in more
reduction in resolution than the boxcar type.) Use this type
if you are measuring condensed-phase samples.
Mathematically weights interferogram data to reduce
ringing effects (side lobes), resulting in lower resolution
than that obtained with the boxcar and Happ-Genzel types.
Some ringing will usually be present with this type. This
setting is normally used only to reproduce the results of
other experiments that used it.
2 Levels This setting adds three points between each data point to
better define band shapes.
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OMNIC User’s Guide 137