function [y]=RaisedCosine(x,alfa)
%function [y]=RaisedCosine(x,alfa)
%x: time vector
%alfa: roll-off factor
%y: pulse response
pigreco=3.141592653589793;
y=zeros(1,length(x));
y(x==0)=1;
y(abs(x*alfa)==1/2)=sinc(1/(2*alfa))*pigreco/4;
y(x~=0 & abs(x*alfa)~=1/2)=sinc(x(x~=0 & abs(x*alfa)~=1/2)).*cos(alfa*pigreco*x(x~=0 & abs(x*alfa)~=1/2))./(1-(2*alfa*x(x~=0 & abs(x*alfa)~=1/2)).^2);