Write an expression for the autocorrelation function \(R_{y}(t)\), where

\[
\begin{equation*}
y(t)=\sum_{n=1}^{5} Y_{n} \operatorname{Rect}\left(\frac{t-n 5}{2}ight) \text { and }\left\{Y_{n}ight\}=\{0.8,1,1,1,0.8\} \tag{5.137}
\end{equation*}
\]

Give an expression for the density function \(S_{y}(\omega)\).