Frequency Accuracy Test; Trace Noise Test - Keysight Technologies N5224A Service Manual

Tests and Adjustments
Performance Tests

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
on page 3-41

Trace Noise Test

Function of the Test: To measure the stability of a signal in the internal source
and receiver system of your analyzer.
Specification Tested: Test Port Input–Trace Noise Magnitude and Trace Noise
Phase
Equipment Used: A test cable.
3-34
"10 MHz Frequency Reference Adjustment"
and then repeat this test.
Keysight N5224A/25A Service Guide