Question

Autocorrelation is a _______ function.

(a) Real and even

(b) Real and odd

(c) Complex and even

(d) Complex and odd

This question was posed to me in an interview.

This intriguing question comes from Spectral Density and Autocorrelation topic in chapter Signals and Spectra of Digital Communications

Answer 1

Right option is (a) Real and even

To explain I would say: According to properties of autocorrelation function it a even function when the frequency value f is real.