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Fourier Transform existed, but I never had intuitive understanding until now

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Re: Fourier Transform existed, but I never had intuitive understanding until now

#21

Post by GianIsAlive »

shaklee3 wrote: post #8
voidhorse wrote: post #6

https://www.dspguide.com/ is a great, general introduction to digital signal processing and includes coverage of the Fourier Transform. I'd recommend checking it out for anyone struggling to grok DSP concepts. This article seems to have the right intent, but I felt the quality of the writing would need to improve for it to become truly useful for learners.

I think the writing was poor, but also there are some things that are just wrong. Like most of the time people sample at 10x Nyquist. That would be a huge waste of processing given that it doesn't give you any more information about the signal than just Nyquist.

I wouldn't say over sampling is wrong. Inefficiency and inaccuracy has different consequences in my opinion. Maybe I'm missing something idk.

Re: Fourier Transform existed, but I never had intuitive understanding until now

#22

Post by GianIsAlive »

voidhorse wrote: post #13
mitthrowaway2 wrote: post #9

Earlier quoted context omitted.

Almost by definition, it does give you more information about the signal than sampling at the Nyquist frequency though? If you have any noise at all, oversampling will be very helpful to improve the signal to noise ratio.

That's true but sampling beyond your target domain bounds seems pointless, right? If, say, you're sampling audio oversampling will just give you a bunch of frequencies you'd end up throwing away regardless. It's extra work for no benefit if the domain already has well-prescribed bounds. I guess it could be useful in cases where you don't have bounds to work against. This comes back to the poor writing, though, as I b…

This is a way better explaination. Thank you! I do agree my writing could be better.

Re: Fourier Transform existed, but I never had intuitive understanding until now

#23

Post by GianIsAlive »

userbinator wrote: post #5

Multiplication is used because when a frequency is present and in phase (meaning peaks are aligned), it would result in more 'positive curves' sitting above the x-axis than negative curves below. This is also the principle behind DSSS modulation ( https://en.wikipedia.org/wiki/Direct-sequence_spread_spectru... ), which is used in numerous communications systems.

Thank you for sharing!
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