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T A K I N G
M E A S U R E M E N T S
3.5 Measuring Harmonics
A harmonics utility is included for one-click measurements of harmonics. To use this
utility, you must span down to 100 KHz or less (narrower spans will give a lower noise
floor), center the signal on the graticule, then select Utilities Harmonics Viewer
from the Menu.
When the sweep completes, you will see the relative amplitude of the fundamental first
four overtones. This utility is for amplitude measurements only. The frequencies
are assumed to be integer multiples of the fundamental. When your measurements
are complete, select Utilities Harmonics Viewer to un-check this utility and
resume normal operation.
3.6 Measuring Phase Noise
A phase noise utility is available to quickly plot SSB phase noise from 1 Hz to 1 MHz.
For best results, it is recommended to use this utility with a high quality OCXO
external timebase of +13 dBm input, with External Reference selected.
To use the utility, center your CW signal on the graticule with a span of 1 KHz or less.
If the frequency is known and timebases are locked, simply enter the frequency as the
CENTER FREQ. Then select Utilities
Your span must be 10 KHz or less to invoke this utility, and the amplitude of the
TCXO timebase contributes more phase noise to these measurements than an external
OCXO 10MHz timebase. Please review the Signal Hound's specifications for phase
noise. If the signal you're measuring has considerably more phase noise than the Signal
Hound, you should be able to get meaningful results using the internal TCXO
timebase. Otherwise, an external OCXO timebase will be needed to make a useful
measurement.
Phase Noise Plot.
Figure 2: Phase Noise Plot
19
signal must be 0-10 dB
below the reference level.
The automated phase noise
measurement takes several
seconds
or
depending
on
settings.
Video Averaging may be
enabled to smooth our any
bumps in the signal. Set to
Video Averaging to 10 to
reduce the uncertainty in
your measurement
The Signal Hound's internal
longer,
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