apodisation.m

Performs free induction decay apodisation. Supports free induction decays of any dimension. To satisfy Fourier transform symmetry requirements, the first elements of the FID in each dimension are divided by 2, except for singleton dimensions and those the user designates inactive.

Syntax

fid=apodisation(spin_system,fid,winfuns,fp_half)

Parameters

fid - the free induction decay. The function expects a column

               vector in the case of 1D FID, a 2D matrix with the time
               origin located at the (1,1) corner point in the case of
               a 2D FID, a 3D matrix with the time origin located at
               the (1,1,1) corner point in the case of a 3D FID, etc.

    winfuns  - a cell array of window function specifications for each
               dimension of the FID in the format {{spec},{spec},...},
               omitting singleton dimensions. The following specifica-
               tions are supported:

        {}           - do nothing in this dimension

        {'none'}     - no window function, but divide the first
                       point by 2 to satisfy the Fourier trans-
                       form symmetry requirement

        {'crisp'}    - multiplied by cos(x)^8 half-bell. First
                       point has x=0, last point has x=pi/2.

        {'exp',k}    - multiplied by exp(-k*x). First point has
                       x=0, last point has x=1.

        {'gauss',k}  - multiplied by exp(-k*(x.^2)). First point
                       has x=0, last point has x=1.

        {'cos'}      - multiplied by cos(x) half-bell. First po-
                       int has x=0, last point has x=pi/2.

        {'sin'}      - multiplied by sin(x) full bell. First po-
                       int has x=0, last point has x=pi.

        {'sqcos'}    - multiplied by cos(x).^2 half-bell. First
                       point has x=0, last point has x=pi/2.

        {'sqsin'}    - multiplied by sin(x).^2 full bell. First
                       point has x=0, last point has x=pi.

        {'kaiser',k} - multiplied by a Kaiser function with the
                       side lobe attenuation factor k. The peak
                       of the Kaiser function is in the middle
                       of the FID.

        {'bad-z1',k} - emulation of a misset Z1 shim, k is a di-
                       mensionless constant proportional to the
                       shim current, a good guess for 1H NMR at
                       600 MHz is 10.

        {'bad-z2',k} - emulation of a misset Z2 shim, k is a di-
                       mensionless constant proportional to the
                       shim current, a good guess for 1H NMR at
                       600 MHz is 40.

    fp_half  - set to false() to disable dividing of the first points
               by 2, this is needed when multiple window functions are
               applied to the same dimension one after another

Outputs

fid - apodised free induction decay

See also

axis_1d.m, contspacing.m, crop_2d.m, ft_axis.m, heterodyne.m, int_2d.m, molplot.m, mri_2d_plot.m, plot_1d.m, plot_2d.m, plot_3d.m, plot_uf.m, slice_2d.m, stack_2d.m, sweep2ticks.m, volplot.m, xyz2pd.m, zoom_3d.m, Kernel utilities

Version 2.11, authors: Ilya Kuprov