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8vs 12-bit scopes in economy class - couple of questions...
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Hella_Wini22:
   1. Why do all of them have such shitty displays ?
      * What's the use of having 12-bit ADC if you can't display all that resolution greatness on a 1024x600 display ? 12-bit means 4096 levels.
And that gets to be displayed usually on a small part of the display. So why don't we see retina-style displays anywhere ?
      * At the time that we see insane big 500Hz displays for gaming crowd, why do all the scopes still have 60Hz models ? I there is one field that could use great, fast displays, that would be scopes, right ? All that famed "digital phosphor persistence" would look much better on such unit, not to mention many other subtle effects of old scopes one could reproduce.
     * Why none of them is using modern-day ARM units with beefy GPUs that could do wonders on scope displays and visualize in 3D many otherwise non-obvious signal properties ? All competitors go for simple marketing bragging rights for lowest hanging fruit they can find and call it a day. And usually even that seems to be just a marketing fluff.
  2.  If one is to do 12-bit properly , one needs much wider datapaths and much beefier ALUs, wider memory, tighter analog circuitry WRT noise etc. If one remains bottlenecked by those, what's the real effect of going to 12-bits?
  3. EEVBlog has said that 8-bits doesn't really make sense any more. Why would that be ?\
Given the significant (~2x) ratio in hardware needed, I wonder why he says that. 8-bit should always be significantly cheaper, all other things being equal.
  4. How much more useful is 12-bit over 8-bit for the most of hobbyistic to prosumer audience ? Scope is all about seeing/visualising of what is going on and much less about measuring.
  5. I guess FFT could be one field where it makes a difference. But even that is limited. FFT on a such scope is more like a toy, compared to real spectrum analyser/VNA. How many are using it and really couldn't do with it on an 8-bit scope ?
Fungus:
Scopes aren't gaming PCs.

The thing about ADCs is that you never get all the bits. Usually the bottom bit is junk (at least) and there's always noise in the system. Really we're talking about 6.5 bit 'scopes vs. 9.5 bit 'scopes (very approximately) at a basic level.

EEVBlog has said that 8-bits doesn't really make sense any more, because... these are basically the same price as the old ones! Why bother with a lower-resolution, non-touch-screen, less functional model?


--- Quote ---8-bit should always be significantly cheaper, all other things being equal

--- End quote ---

Would be true if they designed new 8-bit models using modern chipsets. But they don't.


--- Quote ---How much more useful is 12-bit over 8-bit for the most of hobbyistic to prosumer audience ?

--- End quote ---

These 'scopes do have more pixels on screen than the old ones, and they're way nicer to use. Those old ones feel like antiques in comparison.


Hella_Wini22:

--- Quote ---The thing about ADCs is that you never get all the bits. Usually the bottom bit is junk (at least) and there's always noise in the system. Really we're talking about 6.5 bit 'scopes vs. 9.5 bit 'scopes (very approximately) at a basic level.

--- End quote ---


* Even so, the rest usually ain't pure noise and with oversampling one usually gets more of useful information even out of those.
* Even so, relative proportions still holds. SImple 1024x600 display has  roughly the space for 2 tracks in full res at 8 bit vertically.  New 12-bit scopes have mbarely any more vertcial resolution and yet their ADC resolution quadrupled. Plus they usually have oversampling tricks to get more- up to 16 bit res.

--- Quote ---Would be true if they designed new 8-bit models using modern chipsets. But they don't.
--- End quote ---

Why ? As they age, their price depreciates. We can see this all over the field. THis is why FPGAs that mere moratls get to see, for example use "mature" processes.
Same with microcontrollers. And existing chips get cheaper and cheaper up to the point of obsolescence.


--- Quote ---These 'scopes do have more pixels on screen than the old ones, and they're way nicer to use. Those old ones feel like antiques in comparison.
--- End quote ---

Jut before I was sternly warned that I should stick to the subject and that scopes are about testing, inspecting and service/repair, not about metrology or anything else.
And certainly not about pleasuring oneself. If I was seeking that, I'd be on OnlyFans or something like that.

So my question was, how USEFUL it actually is on a scope ?

SInce scopes are mostly about conveyuing VISUAL information to human operator, one would think that increased ADC resiolution would be closely coupled with matching increase in display resolution... 🙄
Psi:
Put simply, you only use a small range of the total voltage range of the scope when looking at a signal.
So your 0 -> 2V signal showing on screen only covers a tiny range of the bits.

Meaning an 8 bit scope with 256 possible levels ends up very marginal once you consider the number of possible levels being used to represent your 0 - 2V signal.

It's why the voltage measurement on scopes is normally terrible and the noise makes it jump up/down by perhaps 0.1V.

That being said, normally you don't need accurate voltage readings on a scope. So a 8 bit scope doesn't usually cause any problems in 99% of cases.
tautech:

--- Quote from: Psi on September 08, 2024, 08:11:45 am ---Put simply, you only use a small range of the total voltage range of the scope when looking at a signal.
So your 0 -> 2V signal showing on screen only covers a tiny range of the bits.

Meaning an 8 bit scope with 256 possible levels ends up very marginal once you consider the number of possible levels being used to represent your 0 - 2V signal.

It's why the voltage measurement on scopes is normally terrible and the noise makes it jump up/down by perhaps 0.1V.

That being said, normally you don't need accurate voltage readings on a scope. So a 8 bit scope doesn't usually cause any problems in 99% of cases.

--- End quote ---
^^^^
This !
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