Calibration Coefficients Test - Keysight Technologies N5221A Service Manual

Tests and Adjustments
Performance Tests
10.The corrected noise floor in dBm is calculated for a 10 Hz IF bandwidth
using: PNoiseFloor = Ptest – 19.96 dB – (Preset Power – Pref).
If the Analyzer Fails this Test:
— If the analyzer fails this test, replace the A23 mixer brick for a Port 1 or Port
2 failure or the A24 mixer brick for a Port 3 or Port 4 failure, then repeat this
test. Refer to
page
— If the analyzer still fails this test, replace the A12 SPAM board and then
repeat this test. Refer to
page

Calibration Coefficients Test

Function of the Test: To verify the uncorrected calibration coefficients of your
analyzer. The calibration coefficients are specified at the test port without any
cables, so calibrations must be performed in both the forward and reverse
directions to eliminate the effects of the test cable.
Specification Tested: Uncorrected System Performance
Equipment Used:
— Calibration kit
— Test cable
Description of the Test:
Two full SOLT 2-port calibrations are performed on each port pair. Ports 1 and
2 are tested as a pair. Ports 3 and 4 are tested as a pair on 4-port analyzers.
Isolation is turned off during each calibration.
1. A test cable is connected to Port 1.
2. A calibration is performed between the end of the test cable and Port 2.
The Port 2 directivity and source match and the S21 load match are
retrieved from the analyzer.
3. The test cable is moved to Port 2.
4. A calibration is performed between the end of the test cable and Port 1.
The Port 1directivity and source match and the S12 load match are
retrieved from the analyzer.
5. On some older analyzer models, the reflection tracking and transmission
tracking error terms were also specified. For those models, these error
terms are also retrieved from the analyzer.
6. This process is repeated for Ports 3 and 4 on 4-port analyzers.
If the Analyzer Fails this Test:
— Failure of the directivity error term is often due to a faulty test port coupler.
Replace the coupler and repeat this test.
3-38
"Removing and Replacing the A23 and A24 Mixer Bricks" on
7-37.
"Removing and Replacing the A4–A13 Boards" on
7-15.
Keysight N5221A/22A Service Guide