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)

Arguments

   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 specifications are supported:

       {}           - do nothing in this dimension

       {'none'}     - no window function, but divide the first
                      point by 2 to satisfy the Fourier transform
                      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.

Outputs

   fid   - apodised free induction decay

See also

Links to related functions and documentation sections.

Version 2.11, authors: Ilya Kuprov