Enhanced Resolution function in Labview 7.1

[Joost Schouten]

Hello,

a couple weeks ago we received a new PXI rack including a PXI5122 Digitizer. For this digitizer we use the ni-scope drivers in labview 7.1. When we started, the first thing we noticed is the minimum of scope functions in the standard driver (ni-scope). When we compare this with our bench top scope (Lecroy WP940), the conclusion is that we got a lot of work to do to make al these functions in Labview. My question on this forum:

Are there people who already implemented one of the following functions in labview:

Enhanced Resolution
Averaging
Statistical functions (standard deviation ed)
All the standard measurement functions (amplitude, high level, low level etc.)

Especially the Enhanced resolution function would save me a lot of time…

Kind regards,


Joost

[Joost Schouten]

Please Help... Anybody!!

[Dennis_Knutson]

I took a quick look at the specs for the 940 and I get the impression that the scope is normally 8 bits with up to 11 with enhanced resolution. The 5122 is a 14-bit digitizer so you already have much greater resolution without having to switch to a special mode. Looking at the NI-Scope VI Reference Help, I find an extremely long list of measurements available with niScope Read Measurement and niScope Multi Read Measurement functions. I think you'll find all that you're asking for.

[Joost Schouten]

I already found the functions you described, but they only work on a full screen (total acquisition data) and I can't make a cursor function with it. I already found the standard amplitude and time measurements in labview and I use the cursor function of the Graph. I hoped that maybe other people also made standard scope functions...

For the resolution, we want to measure differential phasing gain and need the maximum number of bits to get the highest precision.

[Dennis_Knutson]

To use cursor functins, what you'll have to do is acquire a waveform and then extract the portion between two of the graph's cursors. This is easily done by getting the index position of the cursors with a property node and using Array Subset or Get Waveform Subset on the waveform array. You would then pass the array subset to the regular LabVIEW measurement functions (i.e. Analyze>Waveform Measurements palette).

Like I said, the 5122 is a 14-bit A/D. It does not support flex res like the 5911 so you should always be getting better resolution than your LeCroy.