Keysight Technologies N5247B, Service Manual

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Keysight N5247B Service Guide 3-35
Tests and Adjustments
Performance Tests
7. This power linearity measurement is repeated at several CW frequencies
across the full frequency range of the analyzer.
If the Analyzer Fails this Test:
— Perform the “Source Adjustment” on page 3-56 and repeat this test.
— If the analyzer still fails this test, troubleshoot the source section of the
analyzer and then repeat this test. Refer to “Checking the Source Group” on
page 4-35 .
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:
— Frequency counter
— Test cable
— Adapters
Description of the Test:
This test is performed over the full frequency range of the source synthesizer
board, not the full frequency range of the analyzer. To generate the higher
frequencies, the analyzer passes the synthesizer signal through a series of
frequency doublers. These doublers exactly double the source frequency, so
the deviation from a perfectly accurate frequency is exactly doubled. The
frequency accuracy is specified as the ratio parts per million (ppm), so this ratio
is unaffected by the signal doubling. Therefore, only the frequency accuracy of
the synthesizer board needs to be tested.
1. The analyzer is Preset.
2. The analyzer is set up for a CW measurement on Port 1.
3. A test cable is connected between Port 1 and a frequency counter with
any necessary adapters.
4. The signal frequency is measured and compared with the analyzer source
frequency setting. The difference must be less than the source frequency
divided by 16 for a 1 part per million (ppm) specification.
5. This test is repeated at several frequencies across the range of the source
synthesizer board.
If the Analyzer Fails this Test:
— Verify the accuracy of the 10 MHz OCXO by using a frequency counter to
measure 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 3-55 and then repeat this test.