Consider the Fourier transformable function
![1524_Equation.jpg](https://secure.tutorsglobe.com/CMSImages/1524_Equation.jpg)
By inspection, we see that f is an odd function of t.
It cannot, therefore, be a legitimate autocorrelation function as it violates a fundamental property of the autocorrelation function. Apply the Wiener-Khintchine theorem to arrive at this same conclusion.