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Jonathan Harris

Interleaving Spurs: Offset Mismatches

Jonathan Harris
jonharris0
jonharris0
7/15/2013 9:10:59 AM
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Blogger
Re: Calibration / DC components
@DaeJ, thanks for the question.  The figure is intended just to show that the offset mismatch exists.  It is not necessarily a calibration circuit, sorry for the confusion on that.

@B_Albing, thanks for the comment as well...that is something good to keep in mind.  I'm hoping to dive into a few more of the mismatches in upcoming blogs, but perhaps a good direction afterward may be to discuss some calibration methods...

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B_Albing
B_Albing
7/15/2013 12:17:57 AM
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Editor
Re: Calibration / DC components
@JH - more details on auto-cal methods to remove (or match) DC offset in a future blog, perhaps....

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DaeJ
DaeJ
7/14/2013 5:35:02 PM
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Master
Two ADADC71 chips
I think that in most case, A/D converter chip is used to get A/D from VIN in the circuit. For example, let us say that two ADADC71 chips, 16 bit A/D converter, are used in parallel similar to "Offset mismatch" figure above. I am wondering how this circuit overcomes offset mismatch in this case.

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jonharris0
jonharris0
7/12/2013 3:50:07 PM
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Blogger
Re: Calibration / DC components
Hi Dirceu, yes, a calibration procedure would definitely help.  When doing the calibration you'd need to make sure not to remove the DC content as many applications use content around DC.  As I mentioned, one approach would be to just make the offset of each ADC equal so you don't affect the incoming DC content of the input signal.

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DirceuRodriguesJr
DirceuRodriguesJr
7/12/2013 12:58:45 PM
User Rank
Artist
Calibration / DC components
Jonathan,

  With ADC offset mismatches, a calibration procedures could help? Perhaps some kind of DC restore circuit (op. amp. or software based). I think in measuring devices, for example in the medical field: Unlike the ECG, an oximeter need the DC components of the signal.

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More Blogs from Jonathan Harris
After looking at the performance metrics in the online ADC simulator tool it is a great time to look at another online ADC tool called the Frequency Folding Tool. It is a useful simulator that helps to understand the effects of aliasing in an ADC.
. I received a very good reader question from my last blog post regarding the various parameters that are reported by the tool. Letís take a look at an example and explore the parameters that are returned. In this example we will look at the AD9643-250.
Now letís look at the web-based evaluation tool. This does not require downloaded software to run as it is purely ran from the web
First, to make any ADC operate we need to set up the input stimuli.
We begin this series of blogs by taking a look at ADIsimADC, which is a quite relevant design tool for Jonathan Harris, an applications engineer in ADI's high-speed ADC group.
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