function Y = Expand(X,m,mode);
% Y = Expand(X,m,mode);
%
% Expand(X,m) expands a matrix X by factor m by inserting zero 
% columns.
%
% Optional: Expand(X,m,'full') will also append m-1 zero columns  
% after the last sample.

% Dipl.-Ing. Stephan Weiss, Strathclyde Univ., May 1997. 

if exist('mode'),
  Y = zeros(size(X,1),size(X,2)*m);
else
  Y = zeros(size(X,1),size(X,2)*m-m+1);
end;  

Y(:,1:m:size(Y,2)) = X;