File:DIF-FFT-butterfly-coloured.svg

Summary[edit]

This figure was drawn with LaTeX:

% \documentclass[tikz,convert={outfile=\jobname.svg}]{standalone}
\documentclass[tikz]{standalone}
\usetikzlibrary{automata,positioning}
\usetikzlibrary{math}
\usepackage{relsize}
%\usetikzlibrary{...}% tikz package already loaded by 'tikz' option
\begin{document}
\begin{tikzpicture}% Example:
  \draw[fill=white, draw=white] (-4.5, 0.7) rectangle (6.4, -7.7); 

  % arrow on the right of x's
  \tikzmath{
    \s = 4;
    \spl = 1.8;
    \plocx = 3.5; 
    int \n; 
    for \n in {0,...,3}{
      \x = \n; 
      {
        \draw[color=teal] (0 - \s,-\n) node {$x[\x]$};
        \draw[color=teal] (0.5 - \s,-\n) circle(0.05)[fill=white]; 
        \draw[color=teal] [-latex] (0.55 - \s,-\n) -- (1.4 - \s, -\n); 
        % \draw[color=teal] (1.4 - \s, -\n) -- (1.8 - \s, -\n); 
        \draw[color=teal] (1.4 - \s, -\n + 0.2) node {\tiny $1$};

        \draw[-latex,color=teal] (1.4 - \s, -\n) -- (\plocx - 0.2 - \s, -\n); 
        \draw[-latex,color=teal] (\spl - \s, -\n) circle(0.03)[fill=teal];
        \draw[-latex,color=teal] (\spl - \s, -\n) -- (\plocx - \s, -\n - 3.8); 
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    for \n in {0,...,3}{
      \x = int(\n + 4); 
      {
        \draw[color=blue] (0 - \s,-\n - 4) node {$x[\x]$};
        \draw[color=blue] (0.5 - \s,-\n - 4) circle(0.05)[fill=white]; 
        \draw[color=blue] [-latex] (0.55 - \s,-\n-4) -- (1.4 - \s, -\n - 4); 
        \draw[color=blue] (0.9 - \s,-\n - 4) circle(0.03)[fill=blue];
        \draw[color=blue] [-latex] 
          (0.9 - \s, -\n - 4) --
          (0.9 - \s,-\n-3.5) -- (1.4 - \s, -\n - 3.5); 
        % \draw[color=blue] (1.4 - \s, -\n - 4) -- (\spl - \s, -\n - 4); 
        \draw[color=blue] (1.4 - \s, -\n - 3.5) -- (\spl - \s, -\n - 3.5); 
        \draw[color=blue] (1.4 - \s, -\n - 3.3) node {\tiny $1$};
        \draw[color=blue] (1.4 - \s, -\n - 3.8) node {\tiny $-1$};

        \draw[-latex,color=blue] (1.4 - \s, -\n - 4) -- (\plocx - 0.2 - \s, -\n - 4); 
        \draw[-latex,color=blue] (\spl - \s, -\n - 3.5) -- (\plocx - \s, -\n - 0.2); 
      };
    };
    for \n in {0,...,3}{
      \x = \n; 
      {
        \draw[color=orange] (\plocx - \s,-\n) circle(0.2);
        \draw[color=orange] (\plocx - \s,-\n) node {$+$};
        \draw[-latex,color=orange] (\plocx - \s + 0.2,-\n) -- (1.4, -\n); 
      };
    };
    for \n in {0,...,3}{
      \x = \n; 
      \bbb = 0.5;
      {
        \draw[color=magenta] (\plocx - \s,-\n - 4) circle(0.2);
        \draw[color=magenta] (\plocx - \s,-\n - 4) node {$+$};
        \draw[-latex,color=magenta] (\plocx - \s + 0.2,-\n - 4) -- (\bbb, -\n - 4); 
        \draw[-latex,color=magenta] (\bbb,-\n - 4) -- (1.4, -\n - 4); 
        \draw[color=magenta] (\bbb,-\n - 3.8) node{\scriptsize $W_N$}; 
      };
    };
  }

  % blocks
  \draw[color=orange](1.4, 0.3) rectangle (4, -3.3); 
  \draw[color=magenta](1.4, -3.7) rectangle (4, -7.3); 
  \draw(2.7, -1.5) node[color=orange,text centered, text width=2cm] {$N/2$-point DFT};
  \draw(2.7, -5.5) node[color=magenta,text centered, text width=2cm] {$N/2$-point DFT};

  % E's and O's 
  \foreach \n in {0,...,3} {
    \draw [-latex,color=orange] (4,-\n) -- (4.95, -\n); 
    \draw[color=orange] (5,-\n) circle(0.05)[fill=white]; 
  }
  \foreach \n in {0,...,3} {
    \draw [-latex,color=magenta] (4,-\n  - 4) -- (4.95, -\n - 4); 
    \draw[color=magenta] (5,-\n - 4) circle(0.05)[fill=white]; 
  }
  \tikzmath{
    int \n; 
    for \n in {0,...,3}{
      \x = int(2 * \n); 
      {
        \draw[color=orange] (5.5,-\n) node {$X[\x]$};
      };
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    for \n in {0,...,3}{
      \x = int(2 * \n + 1); 
      {
      \draw[color=magenta] (5.5,-\n - 4 ) node {$X[\x]$};
      };
    };
  }

\end{tikzpicture}
\end{document}

Licensing[edit]

I, the copyright holder of this work, hereby publish it under the following license:

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You are free:

• to share – to copy, distribute and transmit the work
• to remix – to adapt the work

Under the following conditions:

• attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
• share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.

https://creativecommons.org/licenses/by-sa/4.0CC BY-SA 4.0 Creative Commons Attribution-Share Alike 4.0 truetrue