Agilent Technologies e4418b, e4419b manual Expanded Uncertainty, Combined Standard Uncertainty ucy

Measurement Uncertainty Analysis – Power Reference Level Test

Measurement Introduction

Combined Standard Uncertainty (uc(y))

Table B-2: Combined Standard Uncertainty

Symbol			Source of	Value	Probability	Divisor	Ci	Ui
			Uncertainty		Distribution			/∝W
U(V	0	)	Two Voltage	69.65 ∝V	Normal	2	2.129x10-04V/Ω	0.007
			measurements on a
			3458A DMM
U(V	1	)	Two Voltage	69.45 ∝V	Normal	2	1.224x10-02V/Ω	0.426
			measurements on a
			3458A DMM
U(Vcomp)			Voltage measurement	49.25 ∝V	Normal	2	-1.245x10-02V/Ω	0.307
			on 3458A DMM
U(R)			4 wire Resistance	0.0046 Ω	Normal	2	-4.727x10-06W/Ω	0.012
			measurement on
			3458A DMM
U(CF)			Calibration factor for	0.002	Normal	2	-9.696x10-04W	1.070
			Thermistor
U(M		)	Mismatch between the	0.0012	U shaped	√2	-9.454x10-04W	0.885
	s
			DUT and the
			Thermistor
U(Drift)			Drift of 8478B	0.0006	Normal	2	1.00x10-03W	0.6
			Thermistor
U(Rep)			Repeatability of the	0.057 ∝W	Normal	1	1	0.057
			complete measurement
Uc			Combined Uncertainty		Normal			1.515
U1			Expanded Uncertainty	k=2	Normal			3.030

1 Using Agilent’s standard 95.5% confidence the coverage factor is k = 2.00

Expanded Uncertainty

The expanded uncertainty is: U= 3.030 ∝W, as a percent of 1.000 mW: U = 0.303%

B-12 Agilent E4416A/E4417A Service Guide