C Measurement Uncertainty Analysis - Power Reference Level Test
C-146 E4416A/E4417A Power Meters Service Guide
Sensitivity Coefficients (Ci)
I mW Power Measured = f(V
comp
, V
1
, V
0
, R, CF, M
s
)
The sensitivity coefficients should be evaluated using the best estimate of
V
comp
, V
1
, V
0
, R, CF and M
s
. The nominal values for V
comp
, V
1
, V
0
, R, and CF
are:
V
comp
= 4.857 V
V
1
= 83.12 mV V0= 96.17 V
R
1
= 200
CF
2
= 97.5%
= 0.975
The best guess for the Mismatch of the P
s
P
d
is = 1. Output power of the source
as shown earlier is:
This equation shows that if an infinite amount of readings of mismatch were
taken between P
s
P
d
the mean value would equal 1.
Using the above values gives
1 The resistance on the 432A Power meters is set to 200 Ω for this test
2 The average Calibration Factor from the previous six sensors on the Production Line
Ci
V
comp
d
dV
com p
------------------
PM
2 V
1
V
0
–()
4RCFM
s
-------------------------- 2 . 1 2 9 1 0
4– V
Ω
---
×===
Ci
V
1
d
dV
1
---------
PM
2V
comp
2V
1
–
4RCFM
s
---------------------------------- 1.224 10
2–
V
Ω
---
×== =
Ci
V
0
d
dV
0
---------
PM
2–()V
com p
2V
0
+
4RCFM
s
------------------------------------------ 1 . 2 4 5–10
2– V
Ω
---
×== =
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