Keysight Technologies N5224A Service Manual page 62

Tests and Adjustments
Performance Tests
— Two test cables
— Calibration kit
— 10-dB and 20-dB pads if the analyzer does not have an internal step
attenuator
Description of the Test:
For most analyzer models, the receiver compression level is higher than the
maximum source output power. Therefore, an external amplifier is required.
This test also requires that two attenuators be switched in and out of the RF
path. These requirements are met with the use of the Compression Test Set.
The procedure outlined here is for those models which require the test set.
1. The analyzer is Preset. The two test set output attenuators are set to 0 dB.
2. The analyzer is set up for a 201 point CW transmission measurement for
the port pair to be tested with the specified IF bandwidth (typically 1 kHz).
3. A test cable is connected between the analyzer source port and the test
set input port. A test cable is connected to the test set output port.
4. A power sensor is connected to the end of the test cable.
5. For a series of CW frequencies across the analyzer's full frequency range,
the source output level is adjusted to achieve the specified receiver
compression power level (typically the receiver's maximum input power
level).
6. The power sensor is disconnected from the test cable and the cable is
connected to the port to be tested.
7. The analyzer steps through each CW frequency as the absolute log
magnitude value (dBm) and the relative phase for the receiver under test
is read (Pa).
8. The first test set output attenuator is set to 20 dB.
9. The magnitude and phase measurements using the receiver under test are
read: (Pb).
10.The second test set output attenuator is set to 20 dB.
11.The magnitude and phase measurements using the receiver under test are
read: (Pc).
12.The first test set output attenuator is set to 0 dB.
13.The magnitude and phase measurements using the receiver under test are
read: (Pd).
14.The compression for each point is calculated as (Pa–Pb) – (Pd–Pc).
If the Analyzer Fails this Test:
— Run the Receiver Characterization adjustment, and repeat this test.
3-36 Keysight N5224A/25A Service Guide