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Why is the output of the FFT symmetrical?

Mark Newman 15,443 lượt xem 2 years ago
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If you've ever looked at the magnitude spectrum of a signal after performing an FFT, you'll notice that it is symmetrical about a very special frequency called the Nyquist rate.

In this video, we investigate why this happens, what the Nyquist rate is, and what it means for the way you must sample your signal.

Playlist: Understand the output of the FFT
https://www.youtube.com/playlist?list=PLWMUMyAolbNv9c9qMoksBWv_YDn57EJHz

Previous Video:
https://www.youtube.com/watch?v=rUtz-471LkQ&list=PLWMUMyAolbNv9c9qMoksBWv_YDn57EJHz&index=2

Book: How the Fourier Series Works
https://www.amazon.com/dp/B0B1BY5H6T

0:00 - Introduction
1:13 - Ident
1:17 - Welcome
1:58 - In between the samples
3:00 - How the DFT works
5:33 - The Nyquist rate
7:44 - How does the Nyquist rate affects your sampled signal?
8:10 - Aliasing and what it sounds like
9:27 - Another type of symmetry in the Fourier Transform
10:07 - Challenge
10:34 - End Screen

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