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Power Meter 50 MHz Reference Calibration & Verification

Posted: Thu Feb 10, 2011 12:18 pm
by csperrazza
Performance Testing and Calibration of a Power Meter’s 50 MHz Reference

NOTE: This example is based on the Agilent E4418B/E4419B Power Meter. All procedures are modified from Agilent Technologies Part # E4418-90059 Revision G, April 23 2010.

Re: Power Meter 50 MHz Reference Calibration & Verification

Posted: Thu May 03, 2012 11:44 pm
by rdragons
A member of our Metrology department asked me to set these equations up in excel for them.
I can't get equation at line 16 to work with the values provided in the Worked Example of Output SWR values. Another website said I could download an already prepared excel spreadsheet from this forum, but I don't see it.
Does anyone have an excel spreadsheet that does this calculation?

Re: Power Meter 50 MHz Reference Calibration & Verification

Posted: Fri May 04, 2012 10:44 am
by abrush1
I ran through the math myself and found a typo in the equation. The last subscript on Rho under the radical in the numerator should be "100", not "200". As soon as we can get it fixed, we'll post a correction to our Application Note 219.

The attached Excel Spreadsheet develops the equation correctly, and seems to give the same answers Charlie presented (He also used a spreadsheet, in which he got the equation right, but in a slightly different form.)

Re: Power Meter 50 MHz Reference Calibration & Verification

Posted: Fri May 04, 2012 12:37 pm
by rdragons
Thanks. I found the same error about the same time.

On the web there are two documents with the worked example values in disagreement.

http://www.tegam.com/PDF_Files/Resource ... 0Po[2].pdf
Calculate Output voltage reflective coefficient(+) 0.02902246
Calculate Output voltage reflective coefficient(-) 12.04147077

http://www.tegam.com/PDF_Files/Applicat ... 219[2].pdf
Calculate Output voltage reflective coefficient(+) 0.01451123
Calculate Output voltage reflective coefficient(-) 6.020735385

So you can also address the incorrect one in PDF_Files Resources when you fix AN219.

Thanks again.

Re: Power Meter 50 MHz Reference Calibration & Verification

Posted: Fri Aug 31, 2012 9:08 am
by csperrazza
There have been corrections made to the calculation of application note 219. Attached is the application note and the excel spreadsheet for the calculations.