File:Aliasing sinusoidal.gif

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Aliasing_sinusoidal.gif(360 × 223 pixels, file size: 6.47 MB, MIME type: image/gif, looped, 401 frames)

Summary

Description
English: If you don't sample with enough frequency (twice the frequency of the signal you want to measure, as per Nyquist theorem), the signal you recover can be very different from the real one.
Date
Source https://twitter.com/j_bertolotti/status/1221788151741648897
Author Jacopo Bertolotti
Permission
(Reusing this file)
https://twitter.com/j_bertolotti/status/1030470604418428929

Mathematica 11.0 code

sampling = Table[E^j, {j, -4, 2, 0.015}](*Table[10^j,{j,-2,0.7,0.01}]*);
p1 = Table[
   Show[
    ListPlot[Table[{x, Sin[2 \[Pi] x]}, {x, 0, 10, 1/50}], Joined -> True, DataRange -> {0, 10}, PlotStyle -> {Thick, Black}],
    ListPlot[Table[{x, Sin[2 \[Pi] x]}, {x, 0, 20, j}], Joined -> False, DataRange -> {0, 10}, PlotStyle -> {Red, PointSize[0.015]}],
    ListPlot[Table[{x, Sin[2 \[Pi] x]}, {x, 0, 20, j}], Joined -> True, DataRange -> {0, 10}, PlotStyle -> {Red}]
    , Axes -> False
    ]
   , {j, sampling}];
ListAnimate[p1]

Licensing

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.

Captions

If your sampling is not fine enough, the signal you recover can have some very weird shape.

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depicts

27 January 2020

image/gif

a64795b6f7e82ac412e9b7bf25e93701843e989b

6,788,411 byte

223 pixel

360 pixel

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Date/TimeThumbnailDimensionsUserComment
current10:02, 28 January 2020Thumbnail for version as of 10:02, 28 January 2020360 × 223 (6.47 MB)BertoUser created page with UploadWizard
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