Receiver Noise Figure Test - Keysight Technologies N5244/5B Service Manual

Tests and Adjustments
Performance Tests
— If the analyzer fails this test repeatedly, 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
Mixer Bricks" on page
— If the analyzer still fails this test, replace the A12 SPAM board and repeat
this test. Refer to
analyzers with serial numbers prefixed MY/SG/US5150 and below)" on
page 7-20
analyzers with serial numbers prefixed MY/SG/US5201 and above)" on
page

Receiver Noise Figure Test

Function of the Test: To measure the noise figure of the PNA-X noise receiver
system.
Specification Tested: Test Port Input: Option 029 – Receiver Noise Figure
Equipment Used:
— 346C noise source
— BNC cable
Description of the Test:
1. The analyzer is Preset.
2. The 346C noise source is connected to Port 2. A BNC cable is connected
between the noise source and the +28V VDC output on the rear panel of
the analyzer.
3. The analyzer is set to make a noise power density measurement with an
800 kHz noise IF bandwidth using hundreds of points across the full
frequency range of the noise receiver.
4. The ENR data file for the noise source is read into the analyzer.
5. The noise source is turned on and a hot noise response is measured, Phot.
6. The noise source is turned off and a cold noise response is measured,
Pcold.
7. The receiver noise figure for each point is calculated from:
8. This test is repeated for 2, 4, 8, and 24 MHz noise IF bandwidths.
If the Analyzer Fails this Test:
A failure of this test indicates a fault in the noise receiver chain. This can
indicate a faulty assembly or a loose cable.
Keysight N5244B/45B Service Guide
7-48.
"Removing and Replacing the A4–A17 Boards (For
and "Removing and Replacing the A4–A17 Boards (For
7-24.
"Removing and Replacing the A27 and A28
3-43