Uncertainty Equation; Voltage Measurements Uncertainty - Agilent Technologies E4416A Service Manual

Uncertainty Equation

General form of uncertainty equation is:
2
y ( )
u
Hence,
2
( ) ⋅
u 1mW – CV
0
2
⋅ ( )
CCF u CF
Assuming that there is no correlation exists between the 8 input variables.

Voltage Measurements Uncertainty

Since the manufacturer's data is used to determine the standard uncertainty,
the analysis used is the Type A method.
The 3458A DMM Uncertainty is calculated with reference to the Appendix A
of the 3458A Operating Manual.
A normal distribution is assumed, as the 3458A Manual has not specified the
type of distribution used on the measurement.
Both V
measured at the output of the 432A using a 3458A DMM. The approximate
values of V
with the DMM on the 10 V scale.
For the 3458A DMM, the specified accuracy for the 10 volt scale is:
8ppm of Reading + 0.5 ppm of Range
E4416A/E4417A Power Meters Service Guide
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Measurement Uncertainty Analysis - Power Reference Level Test
N N
⎛
⎜
2 2
∑ ∑
( )
= c iu x + 2
⎜
i
⎝
i = 1 i = 1
2
( ) ⋅ ( )
u V + CV u V
0 0 0
2
⋅ ( )
+ CM u M + C
s s Rep
and V values are calculated by subtracting V
0 1
and V for no power (V
comp ref
N
⎞
⎟
∑
( , )
c c u x x
⎟
i j i j
⎠
j = i + 1
2
⋅ ( )
+ CV u V
comp comp
2
⋅ ( ) ⋅
u Rep + C u Drift
Drift
from V
ref
) and for 1 mW power (V
0
C
2 2
⋅ u R ( ) ...
+ CR +
2
( )
as
comp
) are 5 V
1
C-139