function [m]=OTF(l);
% MATLAB HELP:
%
% function [m]=OTF(l);
%
% return the OTF for the given l
%
% aaron birch, may 21, 2002

% this is an estimate of the square of the full disk MTF
% chapter 4, Giles, PhD thesis, Stanford 1999
%
m=exp(- (l/364).^2 );

% medium-l the pixels are binned 2*2, so
% correct the square of the OTF for this
% OTF \propto \sinc( k d / 2) where d is pixel size
k= (l+1/2)/696; %% wavenumber in Mm^(-1)
m=m./sinc( k* 1.3 /2).^2 .* sinc( k*2.6 /2 ).^2 ;

%% take sqrt to get the OTF
m=sqrt(m);