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| 8vs 12-bit scopes in economy class - couple of questions... |
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| Phil1977:
Many reasons for 12-Bit: - All 8-bit scopes I know have visible quantization error on screen, even on the small screens. All 12-bit-scopes I know show super clean lines. - 12 bit give you much more resolution for doing maths, e.g. calculating the difference between two channels or a reference waveform and the channel - An ADC works best if its lowest 1-2 bits are noise. So in a 8-bit scope you practically only have a little more than 6 bits real resolution per sample. Why don't the manufacturers spend more on the display & GPU? I just assume they invest into the ADC and it´s very closely connected RAM. Most of the signal processing magic happens there for very good reasons. And if the pre-processing has been done there, you only need a reasonable but not a very fancy display unit. |
| Fungus:
Example: The Rigol DS1054Z has 400 vertical pixels in the trace display area and an 8-bit ADC, at least one bit of which is mostly noise so really only 7 bits even on a good day. Do you see why 12 bits might be better even though the screen resolution doesn't go up much...? |
| 2N3055:
--- Quote from: nctnico on September 08, 2024, 09:25:26 am --- --- 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. --- End quote --- 12 bit doesn't help to make a scope more accurate. If you look at the specs, you'll see the DC gain accuracy is typically between 1% and 2%. 12 bit doesn't improve that. What more bits does help with is showing more details of a signal. But to actually see those details, you'll need a bigger screen. --- End quote --- Or if you buy propper brand it can be 0.5% DC accuracy... |
| Geoff-AU:
--- Quote from: Hella_Wini22 on September 08, 2024, 06:35:10 am --- 4. How much more useful is 12-bit over 8-bit for the most of hobbyistic to prosumer audience ? --- End quote --- Not very. I have an SDS2000X-HD at work and an SDS-2000X-Plus at home. The Plus is more than adequate for all my needs. --- Quote --- 5. I guess FFT could be one field where it makes a difference. But even that is limited. --- End quote --- The FFT on my HD is just as clunky and horrible to work with as my Plus. As you said, a real spectrum analyser is much better. But for dealing with low frequencies, the scope will do. |
| jasonquin:
Application processor costs. Drive a high-resolution display at high frame rate will put too much burden on the tiny Zynq, which is used in almost every entry level scope. |
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