GATE ECE 2023 | Question: 20

Question

For a real signal, which of the following is/are valid power spectral density/densities?

• A. $\text{S}_X(\omega)=\frac{2}{9+\omega^2}$
• B. $\text{S}_X(\omega)=e^{-\omega^2} \cos ^2 \omega$
• C.
• D.