# Noise model as Sinc function

In "Fundamentals of signal processing: estimation theory", example 3.13 Kay has used a model of band-limited Gaussian noise with a uniform PSD and a sinc autocorrelation function. I expected the autocorrelation function to be a delta function. What I am missing?

Update

What I was missing is that the PSD does not have a phase...

Moreover, the autocorrelation function equals zero at the sampling locations, if the band limit equals the Nyquist frequency.