--- a/scripts/signal/fftshift.m
+++ b/scripts/signal/fftshift.m
@@ -19,6 +19,7 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {} fftshift (@var{v})
+## @deftypefnx {Function File} {} fftshift (@var{v}, @var{dim})
 ## Perform a shift of the vector @var{v}, for use with the @code{fft}
 ## and @code{ifft} functions, in order the move the frequency 0 to the
 ## center of the vector or matrix.
@@ -31,32 +32,55 @@
 ## f = ((1:N) - ceil(N/2)) / N / Dt
 ## @end example
 ##
-## If @var{v} is a matrix, the same holds for rows and columns.
+## If @var{v} is a matrix, the same holds for rows and columns. If 
+## @var{v} is an array, then the same holds along each dimension.
+##
+## The optional @var{dim} argument can be used to limit the dimension
+## along which the permutation occurs.
 ## @end deftypefn
 
 ## Author: Vincent Cautaerts <vincent@comf5.comm.eng.osaka-u.ac.jp>
 ## Created: July 1997
 ## Adapted-By: jwe
 
-function retval = fftshift (V)
+function retval = fftshift (V, dim)
 
   retval = 0;
 
-  if (nargin != 1)
-    usage ("usage: fftshift (X)");
+  if (nargin != 1 && nargin != 2)
+    usage ("usage: fftshift (X, dim)");
   endif
 
-  if (isvector (V))
-    x = length (V);
-    xx = ceil (x/2);
-    retval = V([xx+1:x, 1:xx]);
-  elseif (ismatrix (V))
-    [x, y] = size (V);
-    xx = ceil (x/2);
-    yy = ceil (y/2);
-    retval = V([xx+1:x, 1:xx], [yy+1:y, 1:yy]);
+  if (nargin == 2)
+    if (!isscalar (dim))
+      error ("fftshift: dimension must be an integer scalar");
+    endif
+    nd = ndims (V);
+    sz = size (V);
+    sz2 = ceil (sz(dim) / 2);
+    idx = cell ();
+    for i=1:nd
+      idx {i} = 1:sz(i);
+    endfor
+    idx {dim} = [sz2+1:sz(dim), 1:sz2];
+    retval = V (idx{:});
   else
-    error ("fftshift: expecting vector or matrix argument");
+    if (isvector (V))
+      x = length (V);
+      xx = ceil (x/2);
+      retval = V([xx+1:x, 1:xx]);
+    elseif (ismatrix (V))
+      nd = ndims (V);
+      sz = size (V);
+      sz2 = ceil (sz ./ 2);
+      idx = cell ();
+      for i=1:nd
+        idx{i} = [sz2(i)+1:sz(i), 1:sz2(i)];
+      endfor
+      retval = V (idx{:});
+    else
+      error ("fftshift: expecting vector or matrix argument");
+    endif
   endif
 
 endfunction