Calibration Factor

The VSWR test should be performed prior to running this test.

Overview

The purpose of this test is to characterize the calibration factor of the power sensor at each frequency parameter. The calibration factor created will be used as the correction for the power measured.

The power sensor (UUT) calibration factor uncertainty is stated as an absolute uncertainty. Stating calibration factor uncertainty as an absolute uncertainty allows for a consistent reporting format in TME.

Calibration factor uncertainty can be stated as a relative or an absolute number. Traditionally, calibration factor uncertainty has been stated as a relative number. Measurement uncertainty calculations require that this parameter be a relative term. It is critical that this distinction between absolute and relative uncertainties be understood when performing measurement uncertainty calculations. The power sensor (UUT) relative calibration factor uncertainty can be derived from the absolute calibration factor uncertainty by the following equation.

Relative calibration factor uncertainty = 100% × (Absolute calibration factor uncertainty) / (Calibration factor)

In general, the difference between the relative and absolute uncertainty is less than 10%. This small difference is because calibration factor values tend to be greater than 90% on a typical power sensor.

Standard power sensor

The cal factor uncertainty of the Standard Power Sensor is the most significant contributor to the overall measurement uncertainty of the calibration factor test. Other factors, such as the mismatch and the repeatability of the test system are significant; however, choosing an appropriate reference power sensor is critical to the reported calibration factor uncertainty.

TME recommends using a Standard Power Sensor with Option H84. H84 sensors are calibrated at the required cardinal frequencies using the Standards Lab calibration service. This provides the lowest possible uncertainty.

Required Test Equipment

Instrument	Recommended product	Alternative product	U2000A, U2001A	U2002A	U2004A	U2000B, U2001B	U2000H, U2001H	U2002H
Signal Generators
Signal Generator	E8257D Opt (1EA or 1EU) and (532, 540, 550, or 567)	-	X	X	X	X	X	X
Function Generator	33622A	-			X
Power Supply	87422A	-				X	X	X
Meters
Power Meter^[1]	N1914A	N1912A E4419B	X	X	X	X	X	X
Power Sensor (3 required)^{[2, 3]}	N8481A	8481A	X		X		X
Power Sensor (3 required)^[2]	E9304A	-			X
Power Sensor (3 required)^{[2, 3]}	N8485A	8485A		X				X
Power Sensor (3 required)^{[2, 3]}	N8481H	8481H				X
Power Splitters
Splitter^[3]	11667A	-	X		X	X	X
Splitter^[3]	11667B	-		X				X
Attenuators
Fixed Attenuator	8491A Opt 020	8491B Opt 020			X
Fixed Attenuator	8491B Opt 010	-					X (Alt: 8491A Opt 010 for U2001H)
Fixed Attenuator	8493C Opt 010	-						X
Fixed Attenuator	8491B Opt 003	-			X (Alt: 8491A Opt 003)	X
Adapters
Type-N (m) to 2.4 mm (f)	11903D	-	X		X	X	X
Type-N (m) to BNC (m)	1250-1473	-			X
2.4 mm (f) to 3.5 mm (m)	11901D	-		X				X
3.5 mm (f) to Type-N (m)	08485-60005	-		X				X
Amplifiers
Amplifier	R&K Company Limited A3000-2H-R	-				X	X	X
Amplifier	83020A	-				X	X	X

Table Footnotes:

The following notes apply to power meters:
- N1914A
  - N1914A power meters with serial number prefix prior to MY53040007 require Service Note N1914A-07 which fixes a power supply ground loop. The ground loop injects noise into the measurement circuits which can cause unstable measurements at low (–30 dBm) power levels.
  - Requires minimum firmware version A.01.15 or above to fix a power linearity accuracy issue.
- N1912A requires minimum firmware version A.05.10 or above to fix a power linearity accuracy issue.
For each power sensor model, three units are required to be used as the test equipment below:
- Standard Power Sensor
- Verification Power Sensor
- Buried Power Sensor
Supported power sensor options:
- N8480 Series: STD or CFT
- 8480 Series: Standard Option
- N8485A: STD or CFT and/or 033
- 8485A: Standard Option or 033
Refer to Calibration Data Validation section in Test Equipment page for the calibration options that meet the TME requirement on the test equipment’s calibration data.

Test Setup Illustrations

Select the link below for your power sensor model to go to the test setup illustrations for your model. To expand all, click the Expand All button in the toolbar (webhelp only).