% Author: Dr. Matthias Jung, DL9MJ
% Year: 2020
\begin{circuitikz}
    \draw(0,0)
        node [anchor=south](){E}
        to [short, o-] ++(1,0)
        node [inputarrow](){}
        node [twoportshape, anchor=west](p1){};
    \draw(p1) node [](){\textDelta\textphi};
    \draw(p1.east)
        to [short] ++(1,0)
        node [inputarrow](){}
        node[lowpassshape, anchor=west](lp1){};
    \draw(lp1.north)
        to [short, name={h1}] ++(0,1)
        node [inputarrow, rotate=90](){}
        node[twoportshape, anchor=south](vco){};
    \draw(vco) node [](){VCO};
    \draw(vco.west)
        -| (p1.north)
        node[inputarrow, rotate=-90](){};
    \draw(h1.center)
        to [short, *-o] ++(1,0)
        node[anchor=south](){A};
\end{circuitikz}