What is a Discrete Fourier Transform (DFT) and an FFT?

Explains how the output of a DFT, and a Fast Fourier Transform (FFT), relates to the Fourier Transform of real-time signals. As pointed out in the video, note that the FFT gives the same output as the DFT - it's just a more efficient implementation of the function.

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[exponentmantissa]

Well done. That was the best explanation of DFT I have seen. Easy to follow and the only prerequisite is an understanding of the continuous FT.

[Edu]

I'm some years now trying to understand theses topics, it is VERY tricky, a mosaic of details and concepts, no video yet made me understand it in full, but i'm gathering information and it is getting clear, but still waiting waiting the day I'll figure all out.

[YilinWang-vj]

Thank you so much sir, it helps my final week!

[KF-syud]

Very very clear, you are much much better than professor, thank you.

[parthivchandrak]

Excellent video. Thank you very much for this Professor!!

[SimpleelpmiS]

I know what is DFT (very briefly), your videos are usually great, but I didn't quite understand what you explained below. What am I missing? what else I should revise before I watch this video again to understand?

[weicai]

You are the best teacher I ever met, I su subscribed your channel immediately. I have a question about this video at the ending part, if we sample the signal with time T, then the highest frequency we can get is 1/2T, not 1/T, isn't it?

[bahramhedayati]

Is the FT of sin function drawn correctly?

[JosephLewis-ih]

Walker Lisa White Elizabeth Young Carol

[genderwars]

I understand that you plotted only the magnitudes of the FT. What about the phases? Do they exhibit any property when the signal is discrete or when it repeats?