A type of ([[Finite Impulse Response Filters|finite impulse response filter]]).
$\huge \begin{align}
y_{t} &= \frac{1}{2}\left( x_{t}+x_{t-1} \right) \\
\mathcal{H}(z) &= \frac{1}{2}\left(1 + z^{-1} \right)
\end{align}
$
$\huge \begin{align}
\end{align} $