☰

带有单个样本标签的离散时间序列

tag-icon • tag-icon pgfplots
带有单个样本标签的离散时间序列

在此处输入图片描述

\documentclass[12pt]{beamer}  
\usepackage{pgfplots}  
\usepackage{tikz}  

\begin{document}  
\begin{figure}%  
  \begin{tikzpicture}[scale=0.8]  
    \begin{axis}[axis lines=middle, xtick={-3,-2,...,5,9},  
      xticklabels={-3,{}, -1, 0, 1, {}, {}, {}, 5, $k$},  
      extra x ticks={-2, 2, 3, 4},  
      extra x tick labels={$-2$, $2$, $3$, $4$},  
      extra x tick style={  
        xticklabel style={yshift=0.5ex, anchor=south}},  
      xmin=-5,xmax=11, ytick={\empty}, yticklabels={},  
      ymin=-5, ymax=6, axis on top]  
      \addplot+[ycomb,black,thick] plot coordinates  
      {(-3,3) (-2,-2) (-1,1.5) (0,4) (1,1.5) (2,-1.5) (3, -3)  
        (4,-1) (5,4) (9,5)};  
    \end{axis}  
    \node at (5.1,3.5) {$\cdots$};  
    \node at (0,3.5) {$\cdots$};  
    \node at (0.8,4.5) {\tiny{$x[-3]\delta[n+3]$}};  
    \node at (2.7,4.8) {\tiny{$x[0]\delta[n]$}};  
    \node at (4.2,5) {\tiny{$x[5]\delta[n-5]$}};  
    \node at (6,5.5) {\tiny{$x[\alert{k}]\delta[n-\alert{k}]$}};  
    \node at (6.8,2.2) {$n$};  
    \node at (2.7,5.7) {$x[n]$};  
  \end{tikzpicture}  
\end{figure}  
\end{document}

在本论坛中搜索了一番之后，我找到了此代码和相关情节。我想要的东西的定位是一个临时解决方案。

问题：所有定位都是手动的（通过反复试验）。即使是 x 轴和 y 轴标签，我也必须通过反复试验来定位。这可以自动化吗？当我更改 x 标签的字体大小（例如 \footnotesize）时，它们的对齐方式会变得混乱。

答案1

您可能更喜欢更灵活的自己绘制方法，而不是尝试自定义 PGF 图。以下是使用MetaPost和luamplib. 用 编译lualatex。

在此处输入图片描述

\RequirePackage{luatex85}
\documentclass[border=5mm]{standalone}
\usepackage{luamplib}
\usepackage{unicode-math}
\begin{document}
\mplibtextextlabel{enable}
\begin{mplibcode}
    numeric u, v;
    u = 1cm;
    v = 8mm;
    color pin_shade;
    pin_shade = 1/3[blue,white];

    vardef make_pin(expr X_value, Y_value, label_text) = 
        draw (X_value*u,0) -- (X_value*u,Y_value*v) withpen pencircle scaled 0.8 withcolor pin_shade;
        fill fullcircle scaled 4 shifted (X_value*u,Y_value*v) withcolor pin_shade;
        numeric label_Y, number_Y;
        label_Y = Y_value*v * (abs(Y_value*v)+10)/abs(Y_value*v);
        number_Y = if Y_value > 0: - fi 9;
        label(label_text, (X_value*u, label_Y));
        label("$" & decimal X_value & "$", (X_value*u if X_value=0: +5 fi, number_Y));
    enddef;

    beginfig(1);
    path xx, yy;
    xx = (4 left -- 8 right) scaled u;
    yy = (4 down -- 5 up) scaled v;
    drawarrow xx withcolor .5 white;
    drawarrow yy withcolor .5 white;

    make_pin(-3, 2,"$\scriptstyle x[-3]δ[n+3]$");
    make_pin(-2,-1,"$\scriptstyle x[-2]δ[n+2]$");
    make_pin(-1,+1,"$\scriptstyle x[-1]δ[n+1]$");
    make_pin( 0,+3,"$\scriptstyle x[0]δ[n]$");
    make_pin(+1,+1,"$\scriptstyle x[1]δ[n+2]$");
    make_pin(+2,-1,"$\scriptstyle x[2]δ[n+3]$");
    % etc

endfig;
\end{mplibcode}
\end{document}

答案2

您可以使用软件包提供的常规轴标签pgfplots。要向您的图添加注释，请tikz结合使用节点，axis cs这样您就可以使用您已用于图的坐标。

\documentclass{beamer}
\usepackage{tikz,pgfplots}
\begin{document}
  \begin{tikzpicture}  
    \begin{axis}[axis lines=middle, xtick={-3,-2,...,5,9},  
      xticklabels={-3,{}, -1, 0, 1, {}, {}, {}, 5, $k$},  
      extra x ticks={-2, 2, 3, 4},  
      extra x tick labels={$-2$, $2$, $3$, $4$},  
      extra x tick style={  
        xticklabel style={yshift=0.5ex, anchor=south}},  
      xmin=-5,xmax=11, ytick={\empty}, yticklabels={},  
      ymin=-5, ymax=6, axis on top,
      % axis labels
      xlabel={$n$}, x label style={anchor=north},
      ylabel={$x[n]$}, y label style={anchor=west}]  
      \addplot+[ycomb,black,thick] plot coordinates  
      {(-3,3) (-2,-2) (-1,1.5) (0,4) (1,1.5) (2,-1.5) (3, -3)  
        (4,-1) (5,4) (9,5)};

      % point labels
      \node[anchor=south] at (axis cs:-3,3) {\tiny{$x[-3]\delta[n+3]$}};
      \node[anchor=south west] at (axis cs:0,4) {\tiny{$x[0]\delta[n]$}};  
      \node[anchor=south] at (axis cs:5,4) {\tiny{$x[5]\delta[n-5]$}};  
      \node[anchor=south] at (axis cs:9,5) {\tiny{$x[\alert{k}]\delta[n-\alert{k}]$}};

      % alternative positioning for cdots
      \node at (axis cs:-4.5,1.75) {$\cdots$};
      \node at (axis cs:7.5,1.75) {$\cdots$};
    \end{axis}   
  \end{tikzpicture}  
\end{document}

相关内容