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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
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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
The topic of this blog came up while at the IMS show and one of my colleagues mentioned that I should discuss the ADIsimRF tool as a part of the series. I thought this was a marvelous idea. I’ll have to precursor this discussion with the fact that I am actually an RF guy from my previous employment at an RF company which was my first position when I graduated from college.
One of the questions that appeared on one of the IMS blog posts was about the details of the demonstration I had set up at the Analog Devices booth.
The last and final day of the show is usually has the most relaxed atmosphere and this year that proved to be the case once again. It is the shortest day of the show lasting from just 9:00 AM to 3:00 PM.
After having a pretty good first day of the show, I was looking forward to a good second day and it did not disappoint. The second day of the show on Wednesday is the longest day of the show as the exhibit hours go from 9:00 AM until 6:00 PM (day one is 9:00 AM to 5:00 PM and day three is 9:00 AM to 3:00 PM).
The IMS2015 show is already off to a great start here in sunny Phoenix, Arizona and I hope that those of you attending are enjoying it so far.
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