Consider the infinite series
![204_Equation 3.jpg](https://secure.tutorsglobe.com/CMSImages/204_Equation%203.jpg)
which is an even function of t, thereby satisfying the symmetry property of the autocorrelation function.
Apply the Wiener-Khintchine theorem to confirm that f (t ) is indeed a legitimate autocorrelation function of a weakly stationary process.