% FWHM2SI Converts FWHM to standard deviation
%
% The standard deviation of a normal distribution is calculated,
% calculated, based on its full width at half maximum (FWHM) .
%
% FORMAT si = fwhm2si(w)
%
% OUT si Standard deviation.
% IN w Full width at half maximum.
% 2007-11-29 Created by Patrick Eriksson.
function si = fwhm2si(w)
si = w ./ (2*sqrt(2*log(2)));