OPERATION
37
Average Trace
The average trace is created by averaging a specified number of real time traces. An average trace can
be very effective in reducing the noise floor, since the noise is averaged out, giving the user a better
view of any signals that may be present.
An average trace can also be used to detect a snuggled bug. A snuggled bug is typically a narrow band
RF transmitter tuned very close to the frequency of an existing wide band signal such as an FM radio
station. By tuning the snuggled signal very close to the center frequency of the wide band ambient
signal, the snuggled signal is essentially masked by the demodulation of the radio station signal. With
the average trace, the wideband modulation of the radio station is “averaged” out so that the narrow
band transmitter is easily seen.
CAUTION Using the average trace alone could cause certain types of signals to be missed. Signals such
as spread spectrum or frequency hoppers will disappear into the noise floor in an average trace. Always
use average trace in conjunction with both the peak trace and real time trace to analyze the spectrum.
To display an average trace:
1. From the Main Menu, select Traces or press F2.
2. From the Traces Sub-Menu, select Peak/Avg or press F2.
3. Select the Average icon. An average trace will be displayed.
Several other tasks related to the average trace can be performed from the Traces | Peak/Avg Sub-
Menu.
Save Avg – Save the currently displayed trace to a USB thumb drive or compact flash card
Traces Averaged – adjust the number of real time traces included in the average
To open a previously saved average trace, follow the steps for opening a saved peak trace (see page 36).
Only four saved traces (peak or average) can be open simultaneously.
Persistence View
The persistence view is available in Sweep Mode and displays the trace data from each sweep of the
receiver using fading colors in order to indicate how frequently and recently each signal was
encountered. Transient signals are displayed in darker colors (blues & greens) and fade quickly, whereas
more permanent or persistent signals are displayed in brighter colors (reds and yellows). This enables
the user to easily identify transmit signals even when surrounded by multiple transient signals or noise.
For example, the image below shows the persistence trace being used to display the Wi-Fi band. In the
image, it is obvious that a narrow band signal is "hiding" within Wi-Fi traffic. With the real time trace or
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