Datasheet
Page 25
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1. The noise to power ratio for average only mode is capped at 0.01% for MU calculation purposes.
Process
1. Measured power level ............................................................................................................................................. W
2. Frequency of measured signal (use to get calibration uncertainty and SWR) ................................................... Hz
3. Calculate sensor uncertainty:
Calculate noise contribution (from page 11)
– Average-only mode: Noise = Measurement noise x average-only-mode noise multiplier
– Free-run normal mode: Noise = Measurement noise for video bandwidth setting
– Gated-average normal mode (Trigger normal mode), Noise = Noise-per-sample x noise-per-sample
multiplier
Convert noise contribution to a relative term 1 = Noise/Power .......................................................................... %
Convert zero drift to relative term = Drift/Power = .............................................................................................. %
RSS of above terms = ............................................................................................................................................. %
4. Zero uncertainty
(Mode and frequency dependent) = Zero set/Power = ..................................................................... %
5. Sensor calibration uncertainty (from page 12) .....................................................................................................
(Sensor, measurement mode, frequency, and humidity dependent) = ........................................... %
6. System contribution, coverage factor of 2 ≥ sys
rss
= ............................................................................................ %
(RSS three terms from steps 3, 4 and 5)
7. Standard uncertainty of mismatch
Max SWR (frequency dependent) = ......................................................................................................................
Convert to reflection coefficient, | ρ
Sensor
| = (SWR–1)/(SWR+1) = ......................................................................
Max DUT SWR (frequency dependent) = ..............................................................................................................
Convert to reflection coefficient, | ρ
DUT
| = (SWR–1)/(SWR+1) = .........................................................................
8. Combined measurement uncertainty @ k = 1
U
C
=
(
Max(ρ
DUT
) • Max(ρ
Sensor
)
)
2
+
(
sys
rss
)
2
———————————————————
—————
...............................................................................................
√
2
2
%
Expanded uncertainty, k = 2, = UC • 2 = ................................................................................................................ %
Appendix A
Uncertainty calculations for a power measurement (settled, average power)
(Specification values from this document are in bold italic, values calculated on this page are underlined.)