7.12 Two random processes are given by
$X(t) = n(t) + A \cos(2\pi f_0 t + \theta)$
and
$Y(t) = n(t) + A \sin(2\pi f_0 t + \theta)$
where A and $f_0$ are constants and $\theta$ is a random variable uniformly distributed in the interval $[-\pi, \pi)$. The first term, $n(t)$, represents a stationary random noise process with autocorrelation function $R_n(\tau) = B \Lambda(\tau/\tau_0)$, where B and $\tau_0$ are nonnegative constants.
(a) Find and sketch their autocorrelation functions. Assume values for the various constants involved.
(b) Find and sketch the cross-correlation function of these two random processes.