Tektronix RSA6100A Series, Help Manual

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General Signal Viewing > DPX Spectrum DPX Primer
Figure 2
Figure 3
The traditional swept spectrum analyzer display, Figure 2, uses line traces that can show only one level for
each frequency point, representing the largest, the smallest or the average power. After many sweeps, the
Max Hold trace shows a rough envelope of the stronger laptop signal. +Peak detection was selected for the
other trace in an attempt to capture the weaker but more frequent AP signal, but the bursts are very brief,
so the likelihood of seeing one in any particular sweep is small. It will also take a long time to statistically
capture the entire spectrum of a bursted signal due to the architecture of the swept spectrum analysis.
The DPX spectrum display, Figure 3, reveals much more insight on the same signal. Since it is a
bitmap image instead of a line trace, you can distinguish many different signals occurring within each
update period and/or different version of the same signal varying over time. The heavy band running
straight across the lower third of the graph is the noise background when neither the laptop nor the AP
is transmitting. The red lump of energy in the middle is the ON shape of the AP signal. Finally, the
more delicate spectrum above the others is the laptop transmissions. In the color scheme used for this
demonstration (“Temperature”), the hot red color indicates a signal that is much more frequent than
signals shown in cooler colors. The laptop signal, in yellow, green and blue, has higher amplitude but
doesn’t occur nearly as often as the AP transmissions because the laptop was downloading a
fi le when
this screen capture was taken.
RSA6100A Series Real-Time Spectrum Analyzers Help
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