Service Guide E8361-90001 3-29
PNA Series Microwave Network Analyzers Tests and Adjustments
E8361A Performance Tests (Agilent N2721A Software Package)
Source Power Linearity Test
Function of the Test: To verify that the power level is linear over the analyzer’s
frequency range and to check the linearity of the automatic leveling control (ALC).
Specification Tested: Power Sweep Range and Power Level Linearity
Equipment Used: A test cable. (And a 20 dB attenuator if the analyzer does not have an
internal step attenuator.)
Description of the Test:
1. The Port 2 receiver is used to test Port 1. The receiver linearity is the standard against
which the source linearity is checked.
2. A test cable is connected between Port 1 and Port 2 with 20 dB of attenuation in series
with the cable. This can be done with an internal step attenuator or an external 20 dB
attenuator. This attenuation ensures that the receiver remains in its linear range.
3. The analyzer is set to 25 different points across its frequency range.
4. At each frequency point, the output power level on Port 2 is set to 0.000 dBm and the
power is measured to establish a reference, P
reference
.
5. The source setting is then stepped from −15 to +10 dBm in 1 dB steps and the power is
measured, P
measured
, at each setting.
6. The non-linearity in dB at each frequency point is calculated as:
(P
measured
− P
reference
) − (source setting)
If the Analyzer Fails this Test:
•Perform the “Source Calibration Adjustment” on page 3-42 and repeat this test.
• If the analyzer still fails this test, replace the source assembly and repeat this test.
Refer to “Removing and Replacing the A12 Source 20” on page 7-22.
Frequency Accuracy Test
Function of the Test: To verify the frequency accuracy and range of the analyzer’s source
output.
Specification Tested: Test Port Output–CW Accuracy
Equipment Used: A frequency counter, a test cable, and adapters.
Description of the Test:
1. Port 1 is connected to a frequency counter.
2. A series of frequencies across the band are checked.
If the Analyzer Fails this Test:
• Verify the accuracy of the 10 MHz OCXO by connecting a frequency counter to the
rear-panel 10 MHz REF OUT.
• If the 10 MHz reference is off by more than 10 Hz, perform the “10 MHz Frequency
Reference Adjustment” on page 3-50 and also the “3.8 GHz PMYO Frequency
Adjustment” on page 3-51 and repeat this test.
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