Keysight Technologies N5247B, Service Manual

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Keysight N5247B Service Guide 3-39
Tests and Adjustments
Performance Tests
7. A CW linear measurement sweep is measured for each test point. The
receiver reference power level, Pref, in dBm is calculated for each point
from the mean of each sweep.
8. The test cable is removed and loads are connected to both ports.
9. A CW linear measurement sweep is measured for each test point. The
receiver test power level, Ptest, in dBm is calculated for each point from
the mean of each sweep.
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 “Removing and Replacing the A27 and A28 Mixer Bricks” on
page 7-41 .
— If the analyzer still fails this test, replace the A12 SPAM board and then
repeat this test. Refer to “Removing and Replacing the A4–A17 Boards” on
page 7-18 .
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.