diff Problems/private/remove_dc.m @ 10:207a6ae9a76f version1.0

(none)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Problems/private/remove_dc.m	Mon Mar 22 15:06:25 2010 +0000
@@ -0,0 +1,31 @@
+function [y,dc] = remove_dc(x,columns)
+%REMOVE_DC Remove DC channel from signals.
+%   [Y,DC] = REMOVE_DC(X) removes the DC channel (i.e. the mean) from the
+%   specified (possibly multi-dimensional) signal X. Y is the DC-free
+%   signal and is the same size as X. DC is a scalar containing the mean of
+%   the signal X.
+%
+%   [Y,DC] = REMOVE_DC(X,'columns') where X is a 2D matrix, treats the
+%   columns of X as a set of 1D signals, removing the DC channel from each
+%   one individually. Y is the same size as X and contains the DC-free
+%   signals. DC is a row vector of length size(X,2) containing the means of
+%   the signals in X.
+%
+%   See also ADD_DC.
+
+
+if (nargin==2 && strcmpi(columns,'columns')), columns = 1;
+else columns = 0;
+end
+
+if (columns)
+  dc = mean(x);
+  y = addtocols(x,-dc);
+else
+  if (ndims(x)==2)  % temporary, will remove in future
+    warning('Treating 2D matrix X as a single signal and not each column individually');
+  end
+  dc = mean(x(:));
+  y = x-dc;
+end
+