Anritsu ML2480B Series Maintenance Manual

3-7 50 MHz Calibrator Power Level (All Models) Chapter 3 — Performance Verification
3-12 PN: 13000-00164 Rev. K ML248xx, ML249xA MM
Table 3-3 shows an uncertainty calculation of an ML248xxA reference calibrator power level. The table shows
the resulting expanded uncertainty and each source of uncertainty.
Calibrator Power Level Uncertainty
The formula for standard uncertainty is:
The divisor of each source of uncertainty is determined by the type of probability distribution of each
uncertainty source.
The uncertainty equations of V
0
,V
1
,V
comp
and R are obtained from the Agilent 33420A multimeter accuracy
specifications for 1 year, 23 °C±5 °C as stated in the product’s datasheet. The uncertainties of
V
0
,V
1
,V
comp
and R vary model to model of the multimeter used. The uncertainty of the Effective
Efficiency, EE, is obtained from the thermistor mount 8478B calibration data. The uncertainty of
Mismatch, M, is obtained by taking twice the product of the reflection coefficient magnitude of the 8478B, ,
and the reflection coefficient magnitude of the ML24xxx Reference Calibrator, . The uncertainty of
connector repeatability, CR, is set to 0.1 % (for example, 60 dB for precision connectors).
The sensitivity, C
ix
of each source of uncertainty, except for connector repeatability CR, is the first partial
derivative of the P
meas
equation with respect to the uncertainty source variable. The equation below shows how
the sensitivity of V
comp
and C
iVcomp
is obtained:
Taking the partial first derivative of P
meas
with respect to the variable uncertainty source needs to be done to
obtain sensitivity C
ix
for the rest of the sources of uncertainty, except for connector repeatability CR, which has
a sensitivity set to 0.001 W.
Table 3-3. Uncertainty Calculation of an ML248xx Reference Calibrator Output Power Level
Sources of
Uncertainty
Unit
Readings
Uncertainty
Units
Divisor
Sensitivity
Units
Standard
Uncertainty (W)
Standard
Uncertainty (μW)
V
comp
(V)
5.1627784
1.949 x 10
–4
(V)
1.732
1.950 x 10
–4
(V/Ohm) 2.194 x 10
–8
0.0219
V0
(V)
0.0009813
2.756 x 10
–4
(V)
1.732
–1.300 x 10
–2
(V/Ohm) –2.068 x 10
–6
–2.0680
V1
(V)
0.0784392
2.756 x 10
–4
(V)
1.732
1.280 x 10
–2
(V/Ohm) 2.037 x 10
–6
2.0369
R
(Ω)
200
1.400 x 10
–2
(Ω)
1.732
–4.996 x 10
–6
(W/Ohm) –4.038 x 10
–8
–0.0404
EE
-
0.993600
1.700 x 10
–3
-
1.000
1.006 x 10
–3
W –1.709 x 10
–6
–1.7094
M
-
0.999345
9.728 x 10
–4
-
1.414
–9.998 x 10
–4
W –6.877 x 10
–7
–0.6877
CR
-
0
1.000 x 10
–3
-
1.000
1.000 x 10
–3
W 1.000 x 10
–6
1.0000
Combined Uncertainty (μW) 3.5809
Expanded Uncertainty (K = 2) (mW) 0.00716
Expanded Uncertainty (K = 2) (%) 0.716
Standard Uncertainty X
unc
1
Divisor()
-------------------------
Uncertainty()SensitivityC
ix
()××=
Γ
d
Γ
s
C
iVcomp
d
dV
comp
-----------------
P
meas
[]
d
dV
comp
-----------------
2 V
comp
V
1
V
0
–()V
0
2
V
1
2
–+××
4 R× EE× M×
-----------------------------------------------------------------------------------
2 V
1
V
0
–()×
4 R× EE× M×
---------------------------------------== =

Anritsu ML2480B Series Specifications

General

Brand	Anritsu
Model	ML2480B Series
Category	Measuring Instruments
Language	English