File:Chirp.gif

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Chirp.gif (687 × 298 pixels, file size: 1.2 MB, MIME type: image/gif, looped, 52 frames, 5.2 s)

Captions

Captions

A signal whose spectral content changes with time, e.g. the low frequencies arrive before the high frequencies, is said to be "chirped".

Summary

[edit]
Description
English: A signal whose spectral content changes with time, e.g. the low frequencies arrive before the high frequencies, is said to be "chirped". Notice that in this simple example the overall spectrum of the chirped pulse is wider than the unchirped one, thus keeping the pulse duration constant. If you keep the bandwidth constant, the chirped pulse will stretch in time.
Date
Source https://twitter.com/j_bertolotti/status/1359088862396612612
Author Jacopo Bertolotti
Permission
(Reusing this file)
https://twitter.com/j_bertolotti/status/1030470604418428929

Mathematica 12.0 code

[edit]
a = 5*Sin[\[Pi]/2 \[Tau]]^2
frames = Table[GraphicsRow[{
     ListPointPlot3D[Table[{t, \[Omega], E^(-((\[Omega] - (a t + \[Omega]0))^2/(2 \[Sigma]^2)))/(Sqrt[2 \[Pi]] \[Sigma]) /. {\[Sigma] -> 1, \[Omega]0 -> 10}}, {t, 0, 5, 0.25}, {\[Omega], 5, 40, 0.05}], PlotRange -> All, PlotStyle -> Directive[Black, PointSize[0.01]], Filling -> Bottom, FillingStyle -> Directive[Opacity[0.5], White], ViewPoint -> {2.5, -2.5, 2.5}, AxesOrigin -> {5, 5, 0}, Boxed -> False, Axes -> {True, True, False}, Ticks -> False, Epilog -> {Text[Style["t", Bold], {0.2, 0.2}], Text[Style["\[Omega]", Bold], {0.8, 0.2}]}]
     ,
     Show[
      Plot[Abs[E^(-(1/2) t (t \[Sigma]^2 - 2 I (\[Omega]0)))/Sqrt[2 \[Pi]]] /. {\[Sigma] -> 1, \[Omega]0 -> 10}, {t, -4, 4}, PlotRange -> {-0.5, 0.5}, Axes -> False, PlotStyle -> Gray, PlotPoints -> 50]
      ,
      Plot[Re[E^(-(1/2) t (t \[Sigma]^2 - 2 I (a t + \[Omega]0)))/Sqrt[2 \[Pi]]] /. {\[Sigma] -> 1, \[Omega]0 -> 10}, {t, -4, 4}, PlotRange -> {-0.5, 0.5}, Axes -> False, PlotStyle -> Black, PlotPoints -> 50]
      ]
     }]
   , {\[Tau], 0, 1, 0.05}];
ListAnimate[Join[Table[frames[[1]], {5}], frames, Table[frames[[-1]], {5}], 
 Reverse[frames]]]

Licensing

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I, the copyright holder of this work, hereby publish it under the following license:
Creative Commons CC-Zero This file is made available under the Creative Commons CC0 1.0 Universal Public Domain Dedication.
The person who associated a work with this deed has dedicated the work to the public domain by waiving all of their rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law. You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

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Date/TimeThumbnailDimensionsUserComment
current11:32, 10 February 2021Thumbnail for version as of 11:32, 10 February 2021687 × 298 (1.2 MB)Berto (talk | contribs)Uploaded own work with UploadWizard

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