In [1, p. 62 exercise 3.19] we are asked to find for the multiple sinusoidal process
 $x[n]=\sum\limits_{i=1}^{P}A_{i}\cos(2\pi f_{i}n+\phi_{i})$

the ensemble ACF and the temporal ACF as $M\rightarrow \infty$, where the $\phi_{i}$‘s are all uniformly distributed random variables on $[0, 2 \pi)$ and independent of each other. We are also asked to determine if this random process is autocorrelation ergodic. read the conclusion >