Tikz：MIMO 系统的绘制点

Question

我有以下图片：

并想用点替换中间的箭头，如下图所示：

\documentclass[12pt,a4paper]{scrartcl}
\begin{document}
\usetikzlibrary{decorations.markings}
\usepackage{tikz}    
\begin{figure}[htbp]
\centering
\begin{tikzpicture}
\node (System) [draw,minimum size=24mm] {$\sum$};
\coordinate[above left = of System.west] (a1);
\coordinate[below = of a1] (a2);
\coordinate[below = of a2] (a3);
\coordinate[above right= of System.east] (b1);
\foreach \i [count=\xi from 1] in {2,...,5}
    \coordinate[below=of b\xi] (b\i);
\foreach \i [count=\xi from 1] in {$u_1$,$u_2$,$u_3$}
\draw[-latex'] (a\xi) node[left] {\i} -- (a\xi-| System.west);
\foreach \i [count=\xi from 1] in {$y_1$,$y_2$,$y_3$}
    \draw[-latex'] (System.east |- b\xi) -- (b\xi) node[right] {\i};
\end{tikzpicture}
\caption{Strukturbild eines MIMO-Systems}
\label{fig:mimo}
\end{figure}
\end{document}

并将最后一个重命名为yn和un，以表示可以有 n 个输入或输出。我该如何实现这一点？

Answer 1

• 必须在文档前言中加载包和库：先加载包，然后再加载其库！
• 您的 MWE 错过了两个库（arrows，positioning）
• 我建议不要像下面在 MWE 中那样arrows使用arrows.meta

编辑： 考虑您以下的评论：

\documentclass[12pt,a4paper]{scrartcl}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                positioning}

\begin{document}
    \begin{figure}[htbp]
\centering
    \begin{tikzpicture}[
node distance = 6mm and 12mm
                        ]
\node (System) [draw,minimum size=24mm] {$\sum$};
%
\coordinate[above  left = of System.west, label=left:$u_1$] (a1);
\coordinate[       left = of System.west, label=left:$u_2$] (a2);
\coordinate[below  left = of System.west, label=left:$u_3$] (a3);
%
\coordinate[above right = of System.east, label=right:$y_1$] (b1);
\coordinate[      right = of System.east, label={[xshift=-4mm]left:$\vdots$}] (b2);
\coordinate[below right = of System.east, label=right:$y_n$] (b3);
%
\foreach \i in {1,2,3}
    \draw[-Latex]   (a\i) -- (a\i-| System.west);
\foreach \i in {1,3}
    \draw[-Latex]   (b\i -| System.east) -- (b\i);
    \end{tikzpicture}
\caption{Strukturbild eines MIMO-Systems}
\label{fig:mimo}
    \end{figure}
\end{document}

上述 MWE 现在给出：

Answer 2

可以使用calc库添加小圆圈：

\documentclass[12pt,a4paper]{scrartcl}

\usepackage{tikz}
\usetikzlibrary{decorations.markings,positioning,arrows,calc}

\begin{document}

\begin{figure}[htbp]
\centering
\begin{tikzpicture}
\node (System) [draw,minimum size=24mm] {$\sum$};
\coordinate[above left = of System.west] (a1);
\coordinate[below = of a1] (a2);
\coordinate[below = of a2] (a3);
\coordinate[above right= of System.east] (b1);
\foreach \i [count=\xi from 1] in {2,...,5}
    \coordinate[below=of b\xi] (b\i);
\foreach \i [count=\xi from 1] in {$u_1$,$u_2$}
\draw[-latex'] (a\xi) node[left] {\i} -- (a\xi-| System.west);
\draw[-latex'] (a3) node[left] {$u_n$} -- (a3-| System.west);
%\foreach \i [count=\xi from 1] in {$y_1$,$y_2$,$y_3$}
%    \draw[-latex'] (System.east |- b\xi) -- (b\xi) node[right] {\i};
\draw[-latex'] (System.east |- b1) -- (b1) node[right] {$y_1$};
\draw[-latex'] (System.east |- b3) -- (b3) node[right] {$y_n$};
\fill ($(b1)+(-0.5,-0.75)$) circle (0.03cm);   
\fill ($(b1)+(-0.5,-1)$) circle (0.03cm);   
\fill ($(b1)+(-0.5,-1.25)$) circle (0.03cm);   
\end{tikzpicture}
\caption{Strukturbild eines MIMO-Systems}
\label{fig:mimo}
\end{figure}
\end{document}