Keysight Technologies E4417A Service Manual page 140

C Measurement Uncertainty Analysis - Power Reference Level Test
So the total power incident or measured by the Keysight 432 Power meter is given
by:
(
In all cases P
NOTE
M s Uncertainty
The equation above includes the worst-case mismatch magnitude 2P
the form where various powers can be multiplied by the equation to find
worst-case power levels with respect to mismatch.
From the above mismatch uncertainty equation if Pd is zero, for example, the
NOTE
8478B sensor is exactly 50 ohms then there is NO mismatch uncertainty. This
has not yet been achieved but efforts will be made in the future to try to achieve
as near as possible to a 'zero' level of mismatch uncertainty and hence have
negligible mismatch when calibrating products.
150
2
P o 1 P d 1 P s P d
( ) ) ⁄ ( ±
–
is extremely small therefore P
d
=
2
)
1 1 2P s P d
⁄ ( ± )
Keysight E4416A/E4417A Power Meters Service Guide
²
terms tend to zero leaving.
d
P and is in
s d