Keysight B Series - Very Long Sweep Times; Zero Span Measurements

134 Keysight N9938-90003 User’s Guide
SA (Spectrum Analyzer) Mode (Option 233–Mixed Analyzers)
SA Mode Settings
Some Detector and Video Bandwidth settings will raise the Auto Sweep
Acquisition value greater than 1. In these cases, manually setting Sweep
Acquisition lower than the Auto value may have NO effect.
Learn more about SA mode SwpAcquisition time in the Supplemental Online
Help: http://na.support.keysight.com/fieldfox/help/SupHelp/FieldFox.htm
Very Long Sweep Times
Two primary settings are responsible for the sweep time: Res BW and
SwAcquisition.
— When the sweep time exceeds 1200 seconds (20 minutes), an informational
message: Alert: Very long sweep in progress… is annotated on the screen
for the duration of the sweep.
— When the sweep time exceeds 4000 seconds (about 1 hour), Meas UNCAL
is annotated on the screen. Accuracy cannot be guaranteed.
— InstAlign is always performed only at the beginning of the sweep regardless
of the sweep time. Learn more in “How to Access Individual Alignments”
on page 148.
Zero Span Measurements
When setting the frequency span to Zero, there is NO spectrum of frequencies
to display, so the X-axis units becomes Time. The SA becomes like a tunable
oscilloscope, with the center frequency being the frequency of interest. This
capability is useful for analyzing modulation characteristics, such as pulsed
measurements.
Measurement speed specifications do NOT apply in Temperature Control
Mode. Learn more in “Temperature Control Mode” on page 23.
For non-zero span measurements, refer to “Sweep Acquisition” on
page 132.