Measurement Uncertainty Analysis – Power Reference Level Test
Measurement Introduction
B-2 Agilent E4416A/E4417A Service Guide
Measurement Introduction
In the Power Reference Level Test, the output from the DUT’s 1mW Power Ref
connector is measured.
A 432A Power Meter and an 8478B H01 Power Sensor are required for this test. Also
the H01 power sensor’s calibration factor uncertainty at 50MHz must be no greater
than ±0.2%.
A 3458A DMM is required to read the Vref and Vcomp outputs of the 432A. This is
preferred to estimating an inaccurate visual reading from the 432A front panel.
Define the Measurand
The measurand is the output power of the 1mW reference in the DUT.
Define the Measurement Equation
where,
V
0
is the voltage measured between V
comp
and V
ref
with no power applied, for
example, the reference switched off and after the 432A has been zeroed.
V
1
is the voltage measured between V
comp
and V
ref
with power applied, for example,
the reference switched on.
V
comp
is the voltage between the 432A V
comp
rear connector and chassis ground with
power applied.
R is mount resistance of the 432A meter.
CF is the value of the Calibration Factor of the Thermistor mount at 50MHz.
M
s
is the mismatch magnitude between the DUT reference and the 8478B sensor,
which is equal to:
P
meas
2V
comp
V
1
V
0
–()
⋅⋅
V
0
2
V
1
2
–+
4RCFM
s
⋅⋅ ⋅
---------------------------------------------------------------------------------------------=
M
s
2P
s
P
d
⋅⋅
=
4402serv.book Page 2 Tuesday, October 14, 2003 3:18 PM
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