RF VNA

[JasonS]

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@ASEAN wrote:

Thanks for all the answers, it really helps.

Since NI don't have TRL Calibration kit, can we just use the SOLT standards? Will the results be the same or expect to be less accurate as using transmission lines?

Since it is TRL (Thru, Reflect, Line), Thru is available and the Reflect (Short or Open), what can you recommend for the other Line?

Or how about changing it to TRM (Thru, Reflect, Match) since the counter-part standards are available.

Also, any idea on what are the differences between TRL and TRM? When and where is it good to use for calibration?

Lastly, are there plans for NI to provide TRL kit in the future?

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TRL and TRM are from the same family of calibrations. They use the same algorithm, and the main difference between them is the frequency over which the calibration is valid. In fact, the most general name for this family is LRL -- Line Reflect Line. TRL uses a thru (0 length) as one of the line standards. TRM uses a match as the other line standard (a match emulates an infinite length thru).

The LRL family of calibrations is banded, which means that they are only good over a certain frequency band. The frequencies of validity can be determined based on the difference in length between the two lines.

It is possible to use the SOLT short/open in a TRL calibration, though I'm not certain what the quality of the cal would be. You would need some of the characteristics of the standards to input into the algorithm.

JasonS

Software Engineer

National Instruments

[Titanium]

Is TRL Calibration applicable only with PXIe-5632?

or can we implement also with PXIe-5630? what changes need to modify for it to run in 5630?

THanks.

[Andy_Hinde]

Hello Titanium,

TRL calibration is supported on the PXIe-5632 but not the PXIe-5630.

Thanks,

Andy

[Alikotsa]

I hope its ok to post my question under this thread..

Im using NI PXIe-5632 and Labview 2013.

I need to know how to configure and use limit line tests programmatically? I mean measuring S-parameter trace and checking whether its within the previously configured limit lines or not (getting the PASS/FAIL information).

The example VI's for this HW dont help at all.

Is it even possible in Labview?

-aleksi-

[Andy_Hinde]

Hello Aleksi,

LabVIEW contains a VI called Limit Testing.VI which allows you to input data as well as limits and will return a Pass/Fail. It is a general LabVIEW tool and not limited to NI-VNA application with the PXIe-5630 and PXIe-5632, which is why the examples for limit testing are in general LabVIEW examples and not NI-VNA examples.

Go to LabVIEW and select the Help menu, then chhose Find Examples. Select the Search tab, and then in the search box, type 'limit' and click the Search button. You will see an example in the dialog called Limit Testing Measurement, which shows you how to use the limit testing VIs in LabVIEW.

Regards,

Andy Hinde

National Instruments

[Alikotsa]

Thank you!

That helps.

-aleksi-