5

I'm looking for a specific symbol used to denote a Fourier transform pair in the book:

Brigham, E. O. (1974). "The Fast Fourier Transform", Prentice-Hall. Englewood Cliffs, NJ, 19742.

It looks like this:

Brigham - Fourier pair symbol

I searched extensively on the Comprehensive LaTeX Symbol List by Scott Pakin, but to no avail. I'm not even sure that this symbol exist, but, by chance, does anybody recognise it?

3 Answers 3

9

You could build something from a picture environment.

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{pict2e}
\makeatletter
\newlength{\fsize}
\setlength{\fsize}{\f@size pt}
\newcommand*{\Fp@ir}[2][.4]{%
    \setlength{\unitlength}{#2\fsize}%
    \begin{picture}(1.5,1)(0,.12)
        \roundcap\linethickness{#1 pt}
        \put( 0,.5){\line(1, 1.5){.25}}
        \put( 0,.5){\line(1,-1.5){.25}}
        \put(.1,.5){\line(1, 1.5){.2}}
        \put(.1,.5){\line(1,-1.5){.2}}
        \put(.25,.88){\line(1,0){1}}
        \put(.25,.12){\line(1,0){1}}
        \put(.3,.2){\line(1,0){.9}}
        \put(.3,.8){\line(1,0){.9}}
        \put(1.5,.5){\line(-1, 1.5){.25}}
        \put(1.5,.5){\line(-1,-1.5){.25}}
        \put(1.4,.5){\line(-1, 1.5){.2}}
        \put(1.4,.5){\line(-1,-1.5){.2}}
    \end{picture}%
}
\newcommand*{\Fpair}{\mathchoice%
    {\mathrel{\Fp@ir{1}}}%
    {\mathrel{\Fp@ir{1}}}%
    {\mathrel{\Fp@ir[.3]{.7}}}%
    {\mathrel{\Fp@ir[.25]{.5}}}%
}
\makeatother
\begin{document}
\( \displaystyle a \Fpair b \)
\( \textstyle a \Fpair b \)
\( \scriptstyle a \Fpair b \)
\( \scriptscriptstyle a \Fpair b \)
\end{document}
2
  • Wonderful....very very nice.
    – Sebastiano
    Dec 28, 2020 at 20:39
  • 1
    Wow, yes, this is definitely an all-in-one solution. Thank you @Vincent! Dec 28, 2020 at 22:03
4

The closest thing to that in Unicode is ⏣, the symbol for a benzene ring, which is \benzener in unicode-math, stix or stix2. You could define it as \mathbin{\benzener} or even stretch it out horizontally with a \scalebox.

Or you could draw it in TikZ.

3

From the suggestion of very good user @Davislor, I have created a symbol named \benz not very similar to your picture.

\documentclass[a4paper,12pt]{article}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}
\usepackage{scalerel}
\newcommand{\benz}{\mathbin{\hstretch{3}{\scalebox{.4}{\begin{tikzpicture}
% create the node
\node[draw=black,minimum size=.7cm,regular polygon,regular polygon sides=6] (a) {};
\node[draw=black,minimum size=.55cm,regular polygon,regular polygon sides=6] (a) {};
\end{tikzpicture}}}}}
\begin{document}

$a\benz b$
\end{document}

enter image description here

4
  • 1
    Very lazy user Davislor approves!
    – Davislor
    Dec 28, 2020 at 13:03
  • @Davislor ahahahahah.LOL...But it is not very good my code...but I think that putting the original symbol near a and b it is very ugly. Otherwise the user can you put the image scaling using \includegraphics.
    – Sebastiano
    Dec 28, 2020 at 13:05
  • 2
    This is very ingenious, to say the least. I tried to tweak the proportions, but i still couldn't get it just the same as the one from the book. Still, I'm definitely saving this, I learned something from it! Dec 28, 2020 at 22:02
  • @IsaiaIsmaele Thank you very much for your nice words. All the best.
    – Sebastiano
    Dec 28, 2020 at 22:21

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