function y=FF(x)

mu=sqrt(2*log(2))*30/44.96;
a=exp(-(mu^2)*(x+1).^2);
b=exp(-(mu^2)*(x-1).^2);
c=2*exp(-(mu*x).^2);
d=0.5*((x+1).*erf(mu*(x+1)) + (x-1).*erf(mu*(x-1)) -2*erf(mu*x));
y=(a+b-c+d)/(2*sqrt(pi*mu));
end
