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ADC over sampling

ADC over sampling

ADC over sampling

(OP)
Does anyone have any hands on experience with this concept. An explanation can be found attached to this post. I am looking into an application where I will need 12 bits of resolution and most microcontrollers have only a 10 analog to digital converters.

RE: ADC over sampling

Yes, this works great.  As long as you can spend the time to take extra samples, and your noise is truly random, it works great.  I've oversampled a 1-bit A/D (comparator) and gotten  12-bit resolution (lots of samples!).  Coincidentally, this was on an ASIC designed by Atmel too!  

John D
 

RE: ADC over sampling

(OP)
I was thinking about applying a controlled ramp signal mainly because I am not sure that the noise level in the signal I will be measuring will be large enough. BTW the signals will be amplified pH and ORP signals. So time is not that important in this application.

RE: ADC over sampling

Huh?  You don't think the noise in the signal will be large enough?  Isn't that a good thing?

You can add in "controlled" noise, but that's to account for non-linearities in the lower bits of an ADC and has nothing to do with noise in the signal.  I see no use in applying a "controlled ramp", whatever that may be.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: ADC over sampling

(OP)
Perhaps I did not explain it well enough. Please look at the bottom of page three of the document I supplied a link to. Noise at the input of the ADC must be at least 1 LSB which for the Atmel chip is about 2.5 mv. I fully expect that the noise level to be much lower than that level. For this reason I will probably need to use the technique called "dithering" in the attached document. Dithering is shown in more detail on page six.

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