function [whout]=walsh(n)
whout(1,1)=1;
i=2;
while(i~=2*n)
whout(1:i/2,1+i/2:i)=whout(1:i/2,1:i/2);
whout(1+i/2:i,1:i/2)=whout(1:i/2,1:i/2);
whout(1+i/2:i,1+i/2:i)=-whout(1:i/2,1:i/2);
i=i*2;
end