Measurement Uncertainty Analysis - Power Reference Level Test C
Keysight E4416A/E4417A Power Meters Service Guide 153
Mismatch
The Mismatch uncertainty was previously determined as being:
Consider the model below:
An estimate of the moduli of P
d
and P
s
are each less than a specified value. P
s
and
P
d
each lie within a circle of radius P. Assuming P
d
and P
s
have equal probability
of lying anywhere within the circle the standard uncertainty of Mismatch becomes
P
s
is the reflection coefficient of the source, which is specified as less than 1.05.
VSWR < 1.05
M
s
Uncertainty magnitude()2P
s
P
d
=
This is the worst-case uncertainty for mismatch and occurs when the incident
and reflected waves are 180 degrees out of phase
uM
s
()
maxP
s
maxP
d
⋅
2
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±=
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