Anritsu 0701012 manual Uncertainty Example, Uncertainty of a Measurement Using the Power Sensor

Uncertainty of a Measurement Using the Power Sensor

Uncertainty Example

An example of a measurement uncertainty calculation (for Low Aperture Time mode) is detailed for the MA24106A in Table 3-4 below. The MA24106A is used to measure the power of a 3 GHz, +12.0 dBm and –35 dBm CW signal from a signal source with 1.5:1 VSWR.

Table 3-4.Measurement Uncertainty Example

	Uncertainty		Uncertainty			Adjusted	Adjusted
	Specification		Specification			Uncertainty	Uncertainty
Uncertainty	at +12 dBm		at –35 dBm	Probability		at +12 dBm	at –35 dBm
Term		(%)	(%)	Distribution	Divisor	(%)	(%)
Sensor Linearity		3.0	3.0	Rectangular	3	1.8	1.8
(<+18 dBm)
Noise		0.0	0.8	Normal at 2σ	2	0.0	0.4
Zero Set		0.0	3.2	Rectangular	3	0.0	1.8
Zero Drift		0.0	0.9	Normal at 2σ	2	0.0	0.5
Calibration Factor		1.4	1.4	Normal at 2σ	2	0.7	0.7
Uncertainty
Mismatch		4.0	4.0	Rectangular	3	2.3	2.3
Uncertainty
Combined						3.0	3.6
Uncertainty
(RSS), Room
Temperature
Expanded						6.0	7.1
Uncertainty with
K=2, Room
Temperature
Temperature		1.4	1.4	Rectangular	3	0.8	0.8
Compensation
Combined						3.1	3.6
Uncertainty
(RSS, 0 to 50 °C)
Expanded						6.2	7.3
Uncertainty
with K=2
(RSS, 0 to 50 °C)
Table 3-5.Noise Measurement Uncertainty Calculations
Noise Calculations at 12 dBm (16 mW):
Noise		400 nW/16 mW = 0.0%
Zero Set		1700 nW/16 mW = 0.0%
Zero Drift		500 nW/16 mW = 0.0%
Noise Calculations at –35 dBm (316 nW):
Noise		2.5 nW/316 nW = 0.8%
Zero Set		10 nW/316 nW = 3.2%
Zero Drift		3 nW/316 nW = 0.9%

3-18 MA24106A UG