Comparing Against Expected Data; Figure 260. Noise Plot Showing Obvious Problems - Agilent Technologies e1420b User Manual

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Figure 260 Noise plot showing obvious problems

Comparing against expected data

If none of the problems listed appears on your graph, there still may be
problems or uncertainties that are not obvious at first glance. These
uncertainties can be evaluated by comparing your measurement results
against the following data:
• The noise characteristics expected for your DUT.
• The noise floor and accuracy specifications of the phase noise test system.
• The noise characteristics of the signal source used as the reference source.
The device under test
If you are testing a product for which published specifications exist, compare
the measurement results against the noise and spur characteristics specified
for the product. If the product is operating correctly, the noise graph provided
by the phase noise system should be within the noise limits specified for the
product.
If the device is a prototype or breadboard circuit, it may be possible to
estimate its general noise characteristics using the characteristics of a similar
type of circuit operating in a similar manner.
Agilent E5505A User's Guide
High small
angle noise
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Breaks
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Evaluating Your Measurement Results
Spurs
High noise
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( f ) = -[dBc/Hz] vs. f [Hz]
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