% Eingebunden in paper.tex via \input{blockdiagramm.tex}
% Vektor, reproduzierbar, Schrift passt automatisch zum Paper.
\begin{tikzpicture}[
    node distance=1.4cm and 1.6cm,
    block/.style={draw, thick, rectangle, rounded corners=2pt,
                  minimum height=1.0cm, minimum width=2.0cm,
                  align=center, font=\sffamily\small},
    signal/.style={-{Stealth[length=2.5mm]}, thick}
]
    \node[block]                  (sin)  {Sinus-\\Generator};
    \node[block, right=of sin]    (str)  {Drehzahl-\\Strecke};
    \node[block, right=of str]    (mp)   {Multi-\\plot};
    \node[block, below=of str]    (pc)   {PC\\(BORIS)};

    \draw[signal] (sin) -- node[above]{\scriptsize $u_\mathrm{in}$} (str);
    \draw[signal] (str) -- node[above]{\scriptsize $n_\mathrm{ist}$} (mp);
    \draw[signal] (pc)  -- (sin);
    \draw[signal] (mp)  |- (pc);
\end{tikzpicture}