A=6; x0=1; M=255; f=2; N=100;
for k=1:N
   x2=A*x0;  
      x1=mod (x2,M);   
   v1=x1/256;
   v(:,k)=(v1-0.5)*f;
   x0=x1;
   v0=v1;
end
v2=v
k1=k;
%grapher
k=1:k1;
plot(k,v,k,v,'r');
xlabel('k'), ylabel('v');title('(-1,+1)均勻分布的白噪聲')