8 bit resolution vs. values range

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sg17705
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8 bit resolution vs. values range

Post by sg17705 »

Hi,

I have a probably rookie question: my scope said the vertical resolution is 8 bit, why the API "getvalues" gives me 16-bit signed integers? Shouldn't the samples stay in the range of [0,255] or [-128,127]?

Thanks,
Si

NeilH
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Re: 8 bit resolution vs. values range

Post by NeilH »

Hi

All of our scopes scale their data to 16 bit values when it is returned to the PC

Neil
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sg17705
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Re: 8 bit resolution vs. values range

Post by sg17705 »

Hi Neil,

Thanks for replying. Could you further explain the "scale'' process a little bit? I would assume it is a linear procedure, but I have seen values like 0, 256, but also 513, 770,1027. It seems sometimes the interval is 256, but sometimes it is 257...

Thanks,
Si

NeilH
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Re: 8 bit resolution vs. values range

Post by NeilH »

Hi Si

The 256 raw data levels of 8 bit resolution are scaled to 65536 data levels to be returned as a 16 bit number from the scope to the PC. This scaling is all done on the scope.

Neil
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bennog
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Re: 8 bit resolution vs. values range

Post by bennog »

Tea reason why you don't see multiples of 256 is because your scope is calibrated. It is not just a ADC you read but it is calibrated in the factory so when you read the max value 32000 or -32000 (not 32767) you have exactly 10V or -10V on the input (depending on the range)

Hope this answered your question.

Benno

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