Let X(t) be a continuous-time random process defined by
X(t) = Acos(ωt+Φ)
where the random variables A ~ Uniform (0,1) and Φ ~ Uniform (0,2π) are independent.
The autocovariance function of the process X(t), Cx(t, t_0), is given by
0 1/6 cos(ω(t_1 - t_0))
0 1/4 cos(ω(t_1 - t_0))
0 1/3 cos(ω(t_1 - t_0))
0 1/2 cos(ω(t_1 - t_0))