Keysight Technologies N5511A, User Manual

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290 N5511A Phase Noise Test System User’s Guide
Evaluating Your Measurement Results
Evaluating the Results
Evaluating the Results
This chapter contains information to help you evaluate and output the results
of your noise measurements. The purpose of the evaluation is to verify that the
noise graph accurately represents the noise characteristics of your DUT. To use
the information in this chapter, you should have completed your noise
measurement, and the computer should be displaying a graph of its
measurement results. Storing the measurement results in the Result File is
recommended for each measurement.
These steps provide an overview of the evaluation process.
— Look for obvious problems on the graph such as discontinuity (breaks).
— Compare the graph against known or expected data.
— If necessary, gather additional data about the noise characteristics of the
DUT.
Looking for obvious problems
Some obvious problems on a graph are as follows:
— Discontinuities or breaks in the graph.
— A higher than expected noise level.
— Spurs that you cannot account for.
— Noise that exceeds the small angle criterion line on a
L (ƒ) graph.
Figure 14-1 provides a graphical example of these problems. If one or more of
these problems appear on your graph, refer to “Problem Solving” on page 302
for recommended actions.
Figure 14-1 Noise plot showing obvious problems