Keysight N5224B, Service Manual

Page: 69 / 614

Keysight N5224B/25B Service Guide 3-37
Tests and Adjustments
Performance Tests
— Run the Receiver Characterization adjustment, and repeat this test.
— If the analyzer still 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 7-43 .
Noise State Calibration Coefficients
Noise Floor Test
Function of the Test: To measure the absolute power level of the noise floor for
the analyzer’s receivers.
Specification Tested: Test Port Input–Test Port Noise Floor
Equipment Used:
— Power meter
— Power sensors
— Test cable
— Calibration kit
Description of the Test:
This test uses the source signal out of one analyzer test port as part of the
noise floor measurement on another test port. Port 2 is the source port when
measuring the noise floor of Port 1. Port 1 is the source port when measuring
the noise floor of Ports 2, 3, and 4.
1. The analyzer is Preset.
2. The analyzer is set up for a CW transmission measurement between the
source port and the test port to be measured. The analyzer is set to an IF
bandwidth of 1 kHz and 801 points per sweep.
3. A test cable is connected to the source port.
4. A power sensor is connected to the end of the test cable with any
necessary adapters.
5. For hundreds of frequencies across the analyzer’s full range, a source
power calibration is performed to ensure a flat power response at the end
of the cable at the Preset power level.
IMPORTANT!
For the most current information on the Table 7-2 “Verification,
Performance, and Other Tests and Procedures” column’s content, refer to
https://cal.software.keysight.com/PNA/Help/N7840AWebHelp.htm .