% Author: Prof. Dr. Matthias Jung, DL9MJ
% Year: 2024
\begin{circuitikz}
    \draw[DARCblue](0,0)
        node[anchor=south west](){$f_\text{e1}$ und $f_\text{e2}$}
        to [short, o-] ++(2,0)
        node[inputarrow, DARCblue] {} coordinate(foo1);
    \draw (foo1)
        node[mixer, box, label=Mischer, anchor=west] (mix) {};
    \draw[DARCgreen] (mix.south)
        node[inputarrow, rotate=90, DARCgreen] {}
        to [short,-o, label=${f}_\text{o}$] ++(0,-1.5);
    \draw[DARCorange] (mix.east)
        to [short, >] ++(2,0)
        node[inputarrow, DARCorange](){}
        node[anchor=south east](){$f_\text{ZF}$};
\end{circuitikz}