When I use the 'Gaussian Fit' tool from 'Analysis', after fitting the curve the result log displays several parameters, one of them is "width". Is this the FWHM or ist this value anything else? Couldn't find anything about it in the help index. Regards, Selinger78
The menu item just performs nonlinear fit of the data with the Gauss function. At the end of the fit you can press ctrl-Y or use the menu item Analysis->Nonlinear Curve Fit->Advanced Fitting Tool to bring up the NLSF dialog which would show then current function and parameters. You can then select the Function->Select menu item and click on the Equation radio button at the bottom panel to see the equation.
You will see then that the "w" width parameter in this Gauss equation corrresponds to 2*sigma
So you can compute sigma from the reported w.
As for FWHM, FWHM = 2* sqrt(2*ln(2)) * sigma = sqrt(2*ln(2)) * w (because w = 2 * sigma) = 1.17741 * w
Note that if you want to, you can also define your own Gaussian function with either sigma or fwhm as the parameter instead of the w and then fit with your equation.
Fit Gaussian
Posted - 10/26/2006 : 09:18:36 AM
