%*************************************************************************************
%         This function pertains to the addition of AWGN with mean zero and 
%         parameter 'variance' to an input signal. 
%
%         AUTHOR: Wenbin Luo
%			 DATE  : 04/12/01
%
%			 SYNOPSIS: y = awgn(x,var)
%         x   ---> input signal
%         var ---> variance
%         y   ---> y = x + AWGN    
%***********************************************************************************
function y = awgn(x,var)
    w = randn(1,length(x));
	 w = w - mean(w)*ones(size(w));
    w = sqrt(var)*(w / std(w)); 
    x = x(:); 
    w = w(:); 
    y = x + w;