Receiver Compression Test; Noise Floor Test - Agilent Technologies N5230C Service Manual

PNA Series Microwave Network Analyzers
N5230C

Receiver Compression Test

Function of the Test: To measure the compression at the analyzer's specified maximum power level for the
receivers.
Specification Tested: Test Port Input–Maximum Test Port Input Level
Equipment Used: The compression test set, a power meter, power sensors, two test cables, and a
calibration kit. (And 10-dB and 20-dB pads if the analyzer does not have an internal step attenuator.)
Description of the Test:
1. All measurements are made with a 1 kHz IF bandwidth and 201 points per sweep.
2. The measurements are made separately on each port.
3. The analyzer is set to various CW frequencies across the range of the analyzer.
4. A power sensor is connected to the "signal source point" to be used to test the port. The "signal source
point" may be either the port connector itself, when a short is used, or the end of the test cable, when
the compression test set is used to source the test signal.
5. The analyzer source output level is adjusted to create the maximum power level specified for the
receiver.
6. The power sensor is disconnected and the "signal source point" is connected to the port to be tested.
7. The absolute log magnitude value (dBm) for the reference channel on the port is read.
8. The log magnitude ratioed measurement using the receiver under test is read: (P
9. The source output level is adjusted to decrease the output by 15 dB.
10. The log magnitude ratioed measurement using the receiver under test is read: (P
11. Attenuation of 20 dB is introduced between the source and receiver. This can be done with an internal
step attenuator, an external 10 dB pad (if a short is being used to reflect the signal back into the port), or
an external 20 dB pad (if the signal source is the compression test set).
12. The log magnitude ratioed measurement using the receiver under test is read: (P
13. The source output level is adjusted to produce a reading of Pref (within ±0.03 dBm) for the reference
channel on the source port.
14. The log magnitude ratioed measurement using the receiver under test is read: (P
15. The compression in dB = (P
If the Analyzer Fails this Test:
• Repeat this test. There are no adjustments that can be made.
• Since all four receivers are identical, the suspect failed receiver can be swapped with one of the other
receivers to verify that it is faulty. Swap the suspect receiver and repeat this test. Refer to
and Replacing the A20 Mixer Brick" on page
• If the faulty channel "follows" the receiver, replace the receiver. If the same channel (now with a
different receiver) is still faulty, suspect the associated cabling.

Noise Floor Test

Function of the Test: To measure the absolute power level of the noise floor for the analyzer's receivers.
Service Guide N5230-90024
Performance Tests (Agilent N7840A Software Package)
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7-32.
Tests and Adjustments
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