Sinc function
= Sinc function
{title2=$\operatorname{sinc}(x)=\sin x/x$}
The unnormalized sinc is $\operatorname{sinc}(x)=\sin x/x$, extended by value one at zero. The normalized form is $\sin(\pi x)/(\pi x)$. It is the inverse <Fourier transform> of a frequency interval indicator, so it describes ideal low-pass filtering and the <Shannon scaling function>.