Calibration kit file conversion

[kim jeonghwan]

Any methods or tools to convert commercial calibration kits file, from Keysight, Rohde and Schwarz, and Anritsu, to the file format VNA Tools is using for calibration standards definitions?

[Juerg Ruefenacht]

Hi Jeong Hwan Kim,

Another good reason to attend our VNA Tools training course and learn more about the implications of using only the polynomial definitions of the calibration standards 😊

There is no method for directly converting a calibration kit file from Keysight, Rohde & Schwarz, or Anritsu. And personally, I think it doesn't make sense, because those calibration kit files typically don't contains any information about the complete uncertainty and correlation information of each standard.

It is therefore better to first have your calibration kit characterized by a National Metrology Institute (e.g., METAS) or a calibration laboratory that can provide sdatb files for each standard or a scolcv file for the complete calibration kit.
In the meantime, several cal kit manufacturers offer now their definitions using the sdatb or sdatcv files or at least by request.
You should also check whether the important systematic connector effects are included in their traceability chain. Especially since many NMIs do not yet take these effects into account. Not even in the declared CMC uncertainties!

As a work around, VNA Tools offers in the Database to create under 'Calibration Standard / New Standard' an 'Agilent Model Standard'. This allows to enter the polynomial definitions based on the Keysight model and to add electrical specifications.

Best Regards,
Juerg

[kim jeonghwan]

Hi Juerg,

Thanks for the kind reply. 

However, I could not find an example of making *.xxcv (covariance) file in the distributed VNA Tools package. Does VNA Tools have some functions for calculating or estimating the covariances among e.g. calibration standards in a calibration kit?

Some guidance on this will be appreciated.

Best regards,

Jeong Hwan Kim

2025년 5월 12일 월요일 오후 4시 59분 3초 UTC+9에 juerg.ru...@metas.ch님이 작성:

[Michael Wollensack METAS]

Hi,

you can select multiple sdatb-files in the Data Explorer and right click on them and select 'Save Collection as ...' and select as type scolcv.

The correlation between different sdatb-files is due common uncertainty influences. If they are saved as collection then the covariance matrix per frequency point between those standards is computed and stored in the scolcv-file.

Regards

Michael

[kim jeonghwan]

Hi,

Said that  'The correlation between different sdatb-files is due common uncertainty influences', when sdatb files corresponding to each calibration standard in a calibration kit are loaded into VNA Tools, what would be the  common uncertainty influences and how does VNA Tools know and extract them from each file?

Best regards,

Jeong Hwan Kim

2025년 5월 16일 금요일 오후 11시 7분 54초 UTC+9에 Michael Wollensack METAS님이 작성:

[Michael Wollensack METAS]

Hi,

>  what would be the common uncertainty influences

If an calibration kit was characterized based on a primary calibration using multiple lines then e.g.: the mechanical dimensions would be common uncertainty influences for all standards.

>  and how does VNA Tools know and extract them from each file?

Each influence has an ID. You can see those IDs in the uncertainty budget and as well in the Math Reference of VNA Tools.

Regards

Michael