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What Is the Fourier Transform?

(www.quantamagazine.org)
474 points rbanffy | 17 comments | 04 Sep 25 22:11 UTC | HN request time: 0.906s | source | bottom
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anyfoo ◴[04 Sep 25 23:48 UTC] No.45133536[source]▶
If you like Fourier, you're going to love Laplace (or its discrete counterpart, the z transform).

This took me down a very fascinating and intricate rabbit hole years ago, and is still one of my favorite hobbies. Application of Fourier, Laplace, and z transforms is (famously) useful in an incredibly wide variety of fields. I mostly use it for signal processing and analog electronics.

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1. segfault99 ◴[05 Sep 25 02:11 UTC] No.45134360[source]▶
When I did EE, didn't have access to any kind of computer algebra system. Have 'fond' memories of taking Laplace transform transfer functions and converting to z-transform form. Expand and then re-group and factor. Used a lot of pencil, eraser and line printer fanfold paper for doing the very basic but very tedious algebra. Youngsters today don't know how lucky.. (ties onion to belt, etc., etc.)
replies(4): >>45136650 #>>45136654 #>>45140144 #>>45142196 #
2. taneq ◴[05 Sep 25 09:28 UTC] No.45136650[source]▶
Did you make sproingies from the tear-off side strips of the printer paper, though? That was the best bit. :P
replies(1): >>45137143 #
3. zwnow ◴[05 Sep 25 09:28 UTC] No.45136654[source]▶
No worries, as a self proclaimed youngster I didn't manage to understand Fourier in 2 days and never bothered again. Also had no other prior knowledge to algebra so maybe that's why I struggled. Never perceived algebra as useful in anything programming related, will continue to do so as most problems are solvable without it. I'll let the degree havers do all that stuff.
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4. segfault99 ◴[05 Sep 25 10:47 UTC] No.45137143[source]▶
Of course!
replies(1): >>45148759 #
5. perching_aix ◴[05 Sep 25 11:00 UTC] No.45137201[source]▶
You might find LLMs to be a useful crutch for this to an extent, although it's very easy to take the wrong turn and go off into the deep end. But as long as you keep forcefully connecting it back to practical reality, you can get progress out of it. And of course, never actually make it calculate.
6. Sharlin ◴[05 Sep 25 12:39 UTC] No.45137819[source]▶
> Never perceived algebra as useful in anything programming related

Image, video, and audio processing and synthesis, compression algorithms, 2D and 3D graphics and geometry, physics simulation, not to mention the entire current AI boom that's nothing but linear algebra… yeah, definitely algebra isn't useful in anything programming related.

replies(1): >>45139264 #
7. dsego ◴[05 Sep 25 13:06 UTC] No.45138081[source]▶
Have I got a video for you.

gingerBill – Tools of the Trade – BSC 2025 https://youtu.be/YNtoDGS4uak

8. zwnow ◴[05 Sep 25 14:52 UTC] No.45139264{3}[source]▶
Yea that's not what I work with my guy
replies(1): >>45139273 #
9. Sharlin ◴[05 Sep 25 14:53 UTC] No.45139273{4}[source]▶
You said "anything programming related", not "anything related to my work", "my guy".
10. hnuser123456 ◴[05 Sep 25 15:41 UTC] No.45139859[source]▶
So you're a programmer but you've never assigned a number to a variable or written any math operations? Do you just do string translations or something?
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11. schlauerfox ◴[05 Sep 25 16:06 UTC] No.45140144[source]▶
I just recently got my Computer Engineering degree which is the modern Electronics Engineering and we had a whole class on transforms. We had to do it on paper, but that professor at Cal State LA knew what the heck she was doing. We learned it good.
12. zwnow ◴[05 Sep 25 16:37 UTC] No.45140544{3}[source]▶
I'm talking algebra you need a degree for. Well algebra u learn while getting one that is.
13. IAmBroom ◴[05 Sep 25 17:00 UTC] No.45140819[source]▶
"Book learnin' didn't do me no good no how!"
14. mkipper ◴[05 Sep 25 18:51 UTC] No.45142196[source]▶
Was this professionally or in school? I still did this in an EE program 15 years ago and I can't imagine things have changed since then. I think kids still have to do lots of ugly math in EE classes.
replies(1): >>45145429 #
15. segfault99 ◴[06 Sep 25 00:39 UTC] No.45145429[source]▶
Undergrad. Mid-late 1980s.

I wasn't making point about mathematics qua mathematics. Was thinking that if I were doing EE undergrad today, I'd use SageMath or Mathematica to crunch the mechanical algebraic manipulations involved in doing a z-transform.

16. segfault99 ◴[06 Sep 25 00:41 UTC] No.45145443{3}[source]▶
Plot twist: He's a Haskell guru juggling hylomorphisms blindfolded.
17. echelon ◴[06 Sep 25 12:38 UTC] No.45148759{3}[source]▶
This continued with kids into the 90's. I miss that bit.

https://www.reddit.com/r/nostalgia/comments/b6dptv/folding_t...