Keysight Technologies FieldFox A Series, User Manual

Page: 169 / 756

Keysight N9927-90001 User’s Guide 169
SA (Spectrum Analyzer) Mode
SA Mode Settings
Sweep Acquisition
Available only in non-zero span measurements, when Sweep Acquisition is set
to Auto, the fastest sweep rate is achieved while maintaining full amplitude
accuracy.
However, you can adjust this setting in order to increase the probability of
intercepting and viewing pulsed RF signals.
For example, with
SwpAcquisition set to Auto a pulsed GSM signal is NOT
visible on the FieldFox screen, as shown in a blue trace in the following image.
While watching the trace, increase the SwpAcquisition value until the pulse
spectrum rises out of the noise and reaches its maximum level. Increasing the
SwpAcquisition value beyond this point only slows the update rate (increases
the actual Sweep time readout) but does not improve measurement quality.
Figure 9-5 GSM Signal in Framed Data Format
In the graphic above, a GSM signal in a framed data format; timeslot zero ON;
all others OFF;
PRF = 218Hz, Duty Cycle = 12.5%. The pulsed signal becomes visible on every
sweep update with SwpAcquisition = 50.
How to set Sweep Acquisition
SwpAcquisition is NOT an absolute measure of time, but a relative number
between 1 (fastest) and 5000 (slowest) sweep time. The actual time that was
required to complete a sweep is annotated on the screen.
— Press Sweep 3
.
For zero span measurements, refer to “Zero Span Measurements” on
page 170 .