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Measurement Uncertainty Analysis – Power Reference Level Test
Measurement Introduction
B-8 Agilent E4416A/E4417A Service Guide
Resistance
The uncertainty of the resistance measurement on the 3458A DMM is given from:
with: -
Conditions: - 1 Year Cal and temperature variance +/- 5°C without ACAL
Reference: - 3458A Operating Manual Appendix A
For 1kΩ scale the specified accuracy is;
with: -
1ppm of Reading + 0.1ppm of Range per °C (temp coefficient Tcal ±5 °C)
and, 3ppm of Reading (for factory traceability)
Therefore,
Repeatability
To verify the overall repeatability of the measurement, the test was repeated 20 times,
using the same DUT. For each test cycle, the Power Reference Level Test and the
Power Reference Level Adjust tests, were carried out; at no point during these tests
was the 1mW on the DUT adjusted. The thermistor was disconnected and
reconnected between each test with the sensor position rotated each time. The results
for this evaluation are shown in Table B-1.
Error = (ppm of reading + ppm of range) + (temperature coefficient) + (factory traceability)
10ppm of reading + 0.5ppm of range
UR()
200 10 5 3++()×
1000000
-----------------------------------------------
1000 0.5 0.5+()×
1000000
-----------------------------------------------+
0.0036 0.0010+()
0.0046Ω=
=
=