Home > atmlab > forwardmodel > doppler_lshape.m

doppler_lshape

PURPOSE ^

DOPPLER_LSHAPE Doppler line shape

SYNOPSIS ^

function l = doppler_lshape(f,f0,dd)

DESCRIPTION ^

 DOPPLER_LSHAPE   Doppler line shape

    Calculates the line shape caused by the molecular thermal motion,
    the Doppler line shape. Note that the width is defined HWHM (half
    width at halv maximum).

 FORMAT   l = doppler_lshape( f, f0, dd )
        
 OUT   l    Line shape. Dimensions [f,dd]. 
 IN    f    Frequency vector.
       f0   Centre frequency. Only scalar input allowed.
       dd   Doppler line width, given as FWHM/2. See *doppler_width*.
            Can be a vector.

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

DOWNLOAD ^

doppler_lshape.m

SOURCE CODE ^

0001 % DOPPLER_LSHAPE   Doppler line shape
0002 %
0003 %    Calculates the line shape caused by the molecular thermal motion,
0004 %    the Doppler line shape. Note that the width is defined HWHM (half
0005 %    width at halv maximum).
0006 %
0007 % FORMAT   l = doppler_lshape( f, f0, dd )
0008 %
0009 % OUT   l    Line shape. Dimensions [f,dd].
0010 % IN    f    Frequency vector.
0011 %       f0   Centre frequency. Only scalar input allowed.
0012 %       dd   Doppler line width, given as FWHM/2. See *doppler_width*.
0013 %            Can be a vector.
0014 
0015 % 2006-11-21   Created by Patrick Eriksson.
0016 
0017 
0018 function l = doppler_lshape(f,f0,dd)
0019 
0020 l = zeros( length(f), length(dd) );
0021 
0022 a = sqrt( pi );
0023 
0024 f = vec2col( f );
0025 
0026 dd = dd / sqrt(log(2));
0027 
0028 for i = 1 : length(dd)
0029 
0030   l(:,i) = exp(-((f-f0)/dd(i)).^2) / (a*dd(i));
0031 
0032 end

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