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Posted by rbanffy 9/4/2025

What Is the Fourier Transform?(www.quantamagazine.org)
474 points | 205 commentspage 5
dghughes 9/5/2025||
Bill Hammack The Engineer Guy has a video series on this subject.

https://www.youtube.com/watch?v=6dW6VYXp9HM

idiotsecant 9/5/2025||
Everyone loves the fourier transform because it's easy to understand but everyone ignores the laplace transform, which is much more beautiful, imo, and quite related.
wnoise 7 days ago|
They are quite related, but the Fourier transform seems far more beautiful and generalizable: you can do 2-d, 3-d, etc transforms, and they automatically respect the symmetries of the problems (e.g. rotating the coordinate system rotates the Fourier transform in a corresponding way; frequencies and wave-vectors have meanings). This fully extends to any "nice" abelian group satisfying minor technical conditions, where the mapping is to it's dual group. It even mostly extends to non-abelian groups (representation theory), though some nice properties are lost.

The Laplace transform shines in having nicer convergence properties in some specific cases. While those are extremely valuable for control problems, it really is a much more specialized theory, not nearly as widely applicable. (You can come up with n-d versions. The obvious thing to do is copy the Fourier case and iteratively Laplace transform on each coordinate; the special role of one direction either directly in the unilateral case, or indirectly via growth properties in the bilateral case make it hard to argue that this can develop to something more unifying; the domain isn't preserved under rotation.)

seam_carver 9/5/2025||
Fourier transforms are useful in applications like avoiding moire when downscaling manga and reducing rainbow artifacts in color eink manga. All in kindle comic converter.
ecoled_ame 9/5/2025||
I didn’t have time to read the article, but it’s cool that the position operator and the momentum operator in quantum mechanics are fourier transforms of one another.
Koshkin 9/5/2025||
> The waves that oscillate more quickly — meaning they have more energy

Isn't this essentially a quantum-mechanical concept?

IAmBroom 9/5/2025|
? It's true for all waves in all media.
hbarka 9/5/2025||
Isn’t the Fourier series fundamentals generally a required course in undergraduate college EE field?
sizzzzlerz 9/5/2025||
Of course. It's taught in both mathematics courses as well as engineering. The Fourier transform and it's digital domain cousin, the discrete Fourier transform play such a fundamental role across nearly every engineering discipline as well as physics and many other scientific areas, you cannot get through school without learning about them.
dotnet00 9/5/2025||
Yes, but how many software engineers remember any of that? Most aren't using it.
Joel_Mckay 9/5/2025||
Indeed, because a Golomb ruler optimized DFT is performant... and thus actually useful. lol =3
amai 9/5/2025||
See also

"The LCT generalizes the Fourier, fractional Fourier, Laplace, Gauss–Weierstrass, Bargmann and the Fresnel transforms as particular cases."

https://en.wikipedia.org/wiki/Linear_canonical_transformatio...

jtfrench 9/5/2025||
One of my favorites.
meindnoch 9/5/2025|
A change of basis.
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