Which of the following are true The autocorrelation function

Which of the following are true? The autocorrelation function of a stationary random process (a) must decrease as | | increases, (b) is a function of | | only, (c) must approach a constant as | | increases, or (d) must always be non-negative.

Solution

The following are true,

The autocorrelation function of a stationary random process

(b) is a function of || only

(c) must approach a constant as || increases