Keysight N5224B, Руководство по обслуживанию

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Keysight N5224B/25B Service Guide 3-35
Tests and Adjustments
Performance Tests
Specification Tested: Test Port Input–Trace Noise Magnitude and Trace Noise
Phase
Equipment Used: A test cable.
Description of the Test:
Trace Noise is a calculation of the standard deviation of a 201 point CW
measurement. In a healthy analyzer, this measurement is only affected by the
sampling error of the analog to digital converters on the SPAM board.
Ports 1 and 2 are tested as a pair using S21 and S12 measurements. Ports 3
and 4 are similarly tested as a pair on 4-port analyzers using S43 and S34
measurements.
1. The analyzer is Preset.
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).
Both a magnitude and a phase trace are displayed.
3. A test cable is connected between the port pair to be tested.
4. The analyzer is set to a series of CW frequencies across its full frequency
range. The analyzer’s trace statistics function is used to calculate the
standard deviation of both the magnitude trace and the phase trace.
5. These standard deviation values are reported as the analyzer’s trace noise
and are compared with the Trace Noise magnitude and phase
specifications.
If the Analyzer Fails this Test:
A failure of this test indicates a fault in the receiver’s IF chain between the
mixer and the A12 SPAM board. This can indicate a faulty assembly or a loose
cable.
— Check for proper torquing of all semi-rigid cables in the receiver chain, and
then repeat this test.
— If the analyzer still fails this test, replace the A12 SPAM board and repeat
this test. Most failures are due to this board. Refer to “Removing and
Replacing the A4–A17 Boards” on page 7-19 .
— If the analyzer still fails this test, replace the mixer module for the failing
receiver, and then repeat this test.
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:
— U3070AK01 or Z5623A Option K01 Compression Test Set