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function Y=zerohold(X,N) 
%ZEROHOLD Oversample the input X, by N times, using zero order hold. 
%	  Y=zerohold(X,N) 
%	  If X is a matrix then each row is over sampled 
% 
%	  See : SUBSAMP 
%	  Copyright (c) Eric Lawrey July 1997 
 
%Modifications: 
%	10/7/97	Started writing the function. This function is finished 
%		and tested. It appears to work. 
%	3/8/97	Changed back to the older algorithum of doing zero hold 
%		by copy one column at a time. This was because the other 
%		algorithum doesn't work for multiple rows of data. 
if N > 0, 
	if N > 1, 
		N = round(N); 
		Y = zeros(size(X,1),size(X,2)*N);	%initialize Y 
 
		for k = 1:size(X,2)*N 
			Y(:,k) = X(:,ceil(k/N));	%Copy multiple X values into Y 
		end 
%		for k = 1:N:size(X,2)*N,	%Copy multiple X values into Y 
%			Y(:,k:k+N-1)=X(:,ceil(k/N)).*ones(size(X,1),N); 
%		end 
	else 
		Y=X; 
	end 
end