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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

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.

GianIsAlive 4y ago
I wouldn't say over sampling is wrong. Inefficiency and inaccuracy has different consequences in my opinion. Maybe I'm missing something idk.
mitthrowaway2 4y ago
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.
- shaklee3 4y ago
  for band limited signals the snr is not increased by oversampling
- voidhorse 4y ago
  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 believe the author meant to indicate that the industry standard for sampling audio is 10x their cited sampling rate of 2000HZ in the text (though this is incorrect, too. Audio is sampled at 44100HZ because the general upper bound on hearing is 22000HZ, so by Nyquist's theorem, sampling at 44100 gives you enough range to avoid aliasing within the 0-22000 band).
  - GianIsAlive 4y ago
    This is a way better explaination. Thank you! I do agree my writing could be better.
  - fsckboy 4y ago
    Here's what I've never understood, isn't Nyquist sampling discrete in time but continuous in amplitude? If the amplitude is instead (as is normal in digital) being sampled discretely (in steps), wouldn't that introduce errors, and wouldn't more samples make up for these errors? what would Nyquist in amplitude, continuous in time look like? that's sort of a class D amplifier, and even sort of CVSD.
    - ajb 4y ago
      There are Sigma Delta ADCs, which sample quantised to one bit at a higher frequency. They need to do some processing in the analogue domain though. IIRC you need to multiply the sample rate by 4*N to get the equivalent of an N but DAC

GianIsAlive 4y ago

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

mitthrowaway2 4y ago

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.

shaklee3 4y ago
for band limited signals the snr is not increased by oversampling
voidhorse 4y ago
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 believe the author meant to indicate that the industry standard for sampling audio is 10x their cited sampling rate of 2000HZ in the text (though this is incorrect, too. Audio is sampled at 44100HZ because the general upper bound on hearing is 22000HZ, so by Nyquist's theorem, sampling at 44100 gives you enough range to avoid aliasing within the 0-22000 band).
- GianIsAlive 4y ago
  This is a way better explaination. Thank you! I do agree my writing could be better.
- fsckboy 4y ago
  Here's what I've never understood, isn't Nyquist sampling discrete in time but continuous in amplitude? If the amplitude is instead (as is normal in digital) being sampled discretely (in steps), wouldn't that introduce errors, and wouldn't more samples make up for these errors? what would Nyquist in amplitude, continuous in time look like? that's sort of a class D amplifier, and even sort of CVSD.
  - ajb 4y ago
    There are Sigma Delta ADCs, which sample quantised to one bit at a higher frequency. They need to do some processing in the analogue domain though. IIRC you need to multiply the sample rate by 4*N to get the equivalent of an N but DAC