N1923A Datasheet, PDF (16/19 Pages) Keysight Technologies – Wideband Power Sensors

16 | Keysight | 8990B Peak Power Analyzer and N1923A/N1924A Wideband Power Sensors - Data Sheet
Appendix A
Uncertainty calculations for a power measurement (settled, average power)
[Specification values from this document are in bold, values calculated on this page are underlined.]
Process
1. Power level ..............................................................................................................................................
W
2. Frequency ................................................................................................................................................
3. Calculate meter uncertainty:
Calculate noise contribution
Noise = Noise-per-sample x noise per sample multiplier
Convert noise contribution to a relative term ¹ = Noise/Power .........................................................
%
Instrumentation linearity .....................................................................................................................
%
Drift .........................................................................................................................................................
%
RSS of above three terms ≥ Meter uncertainty = ............................................................................
%
4. Zero uncertainty
(Mode and frequency-dependent) = Zero set/Power = ...................................................................
%
5. Sensor calibration uncertainty
(Sensor, frequency, power and temperature-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
( ) ( ) ^{UC =}
Max(ρ_DUT ) _⦁ Max(ρ_Sensor )
2
+
√2
sys_rss ²
2
...................................................................
%
Expanded uncertainty, k = 2, = UC _⦁ 2 = ...............................................................................................
%
1. The noise-to-power ratio is capped for powers > 100 μW, in these cases use: Noise/100 μW.