Show that the autocorrelation function of the output of a discrete linear system with impulse response \(h(n)\) is given by

\[R_{Y}(n)=\sum_{k=-\infty}^{\infty} R_{X}(n-k) C_{h}(k)\]

where

\[C_{h}(k)=\sum_{r=-\infty}^{\infty} h(k+r) h(r)\]