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Uncertainty Calculation with N1912A Power Meter

Question asked by mikekoba on May 27, 2010
Hello,

I am trying to calculate the uncertainties involved with a N1912A power meter with a N1922A power sensor.  I'm looking at the N1912A datasheet and i've been trying to figure out the worked example for the uncertainty analysis and I have some questions.

1. In Step 8 to calculate the combined k=1 uncertainties, I cannot compute 2.23%.  I get 2.04%  Why?
2. For determining standard uncertainty of mismatches, I believe it should be sqrt(2)*|Gamma1|*|Gamma2|.  The datasheet example uses |Gamma1|*|Gamma2|/sqrt(2).  Although, even if I change to the one I think is correct, i still get 2.041%, not 2.23% as shown.

Is there an error in the worked example?

Thank you in advance!  

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