Calibration Coefficients Test - Keysight N5227A Service Manual

PNA Series Microwave Network Analyzers
N5227A

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 S load match are retrieved from the analyzer.
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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 S load match are retrieved from the analyzer.
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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.
• Failure of the source or load match error terms is due to faulty hardware between the test port and the
internal source. Refer to
the suspected faulty component or assembly.
Service Guide N5227-90001
Chapter 7, "Repair and Replacement Procedures,'
Tests and Adjustments
Performance Tests
for instructions on replacing
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