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PXI-4496 vs PXI-4462 resolution

Is it possible that for a same voltange range, the PXI-4462 card has a lower resolution that the PXI-4496, even if they are both 24-bit?

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Message 1 of 7
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explain what you mean by "lower" and by "resolution".

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Message 2 of 7
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Both cards are 24-bits.

 

Using the PXI-4496, on a +/-1 Volt range, the 24 bits seems to be dictributed over à 2.2 V range (-1.1 to +1.1).

Using the PXI-4462, on the equivalent +/-1 Volt range, the 24 bits seems to be distributes over a 3.8 V range (-1.9 to +1.9).

 

By resolution, I mean the smalles voltage increment we can measure, i.e. Q= (Vrangemax-Vrangemin)/(2^24).

 

 

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Message 3 of 7
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Hi Beniot100,

 

How are you determining the range over which the modules "seem" to be distributing the 24 bits of resolution? How are you measuring this? What else is connected? What kind of noise might the system be seeing? Can you attach some screen shots or any other helpful data? Thanks!

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Message 4 of 7
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Hi Jeff,

 

I am using an application developped by a third party, so I have to rely on them to make sure the configuration is done properly.

 

I think we can simplify the question to : Is there a physical difference between the two cards that would lead to a lower resolution. Could it be related to the fact that one card is pseudo-differential and the other can operate full differential?

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Message 5 of 7
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The smallest detectable change is defined by the the range/2^resolution, which would be the same for each card given the same range. 

RF R&D
National Instruments
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Message 6 of 7
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That is an interesting test.  Measuring voltage range.  Because right now I am having the same kind of issue with the 4464 and the 4462.  I have not payed attention tot he raw voltage range but the computed FFTs do not look as sharp with the 4464 compared to the 4462. 

My gut feeling is the 4462 is a better device.  But I need an empirical test to prove it.

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Message 7 of 7
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