C Measurement Uncertainty Analysis - Power Reference Level Test
C-148 E4416A/E4417A Power Meters Service Guide
Combined Standard Uncertainty (uc(y))
Expanded Uncertainty
The expanded uncertainty is: U= 3.030 mW, as a percent of 1.000 mW: U =
0.303%
Ta bl e C - 2 Combined Standard Uncertainty
Symbol Source of Uncertainty Value Probability
Distribution
Divisor Ci Ui/μW
U(V
0
) Two Voltage measurements
on a
3458A DMM
69.65 μW Normal 2 2.129x10
-04
V/Ω 0.007
U(V
1
) Two Voltage measurements
on a
3458A DMM
69.45 μW Normal 2 1.224x10
-02
V/Ω 0.426
U(V
comp
) Voltage measurement on
3458A DMM
49.25 μWNormal 2 −1.245x10
-02
V/Ω 0.307
U(R) 4 wire Resistance
measurement on
3458A DMM
0.0046 Ω Normal 2 −4.727x10
-06
V/Ω 0.012
U(CF) Calibration factor for
Thermistor
0.002 Normal 2 −9.696x10
-04
V/Ω 1.070
U(M
s
) Mismatch between the
DUT and the Thermistor
0.0012 U shaped −9.454x10
-04
V/Ω 0.885
U(Drift) Drift of 8478B Thermistor 0.0006 Normal 2 1.00x10
-03
V/Ω 0.6
U(Rep) Repeatability of the
complete measurement
0.057 μW Normal 1 1 0.057
U(c) Combined Uncertainty Normal 1.515
U
*
Expanded Uncertainty k = 2 Normal 3.030
* Using Agilent's standard 95.5% confidence the coverage factor is k = 2.00
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com