|
2. Multiply the trace by an apodization function. Eight (8) apodization functions are supported by Thermo Galactic:
Triangular: 
For single-sided interferograms, A(x) = 1 on the interval [0,zpd]
Boxcar: No apodization is applied
Norton-Beer:
|
C0 |
C1 |
C2 |
C3 |
C4 |
| Weak: |
0.384093 |
-0.087577 |
0.703484 |
0 |
0 |
| Medium: |
0.152442 |
-0.136176 |
0.983734 |
0 |
0 |
| Strong: |
0.045335 |
0 |
0.554883 |
0 |
0.399782 |
Happ-Genzel: 
Bessel: 
Cosine: 
3. Expand the number of points in the trace by the zero fill factor and then
to the next even power of 2 points.
4. Perform a Phase correction:
a) Take an even power of 2 points of the trace on each side of the centerburst
b) Perform a Triangular apodization using a function that equals 0 at the endpoints and 1 at the centerburst.
c) Interpolate the Phase array to twice the point density of the output trace before truncation. Thermo supports two interpolation algorithms: Linear and Fourier zerofill.
5. If the interferogram is single-sided, a linear contrast correction is applied by multiplying the trace by the following function:
y = (2/zpd)x on the interval [0,2*zpd] where zpd = the distance to the centerburst.
6. Swap the portions of the trace to the left and right of the centerburst.
7. Apply a Fast Fourier Transform.
8. Multiply by the Phase array.
9. Take the real part of the resulting spectrum.
10. Multiply by the number of points and the scale factor
11. Truncate the trace to the specified limits.
12. A background file can then be used to convert the resulting single-beam spectrum to Absorption, Transmission or Kubelka-Munk units. | 
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