Agilent Technologies ESA Series User's/Programmer's Reference page 140

Front-Panel Key Reference
SPAN X Scale
frequency is displayed in the time domain (the x-axis is displayed in
units of time), like a conventional oscilloscope.
Sweep times faster than those in the frequency domain display mode
are available if Option AYX or B7D are installed.
Resolution Bandwidths less than 1 kHz are unavailable when in zero
span if the sweep time is being achieved by utilizing the Option AYX or
B7D.
Key Access:
Sweep times that would require Option AYX or Option B7D are not
NOTE
available in zero span if the Resolution Bandwidth is less than 1 kHz.
Zero Span is not available when
NOTE
in the segmented sweep function can be set to zero span by setting the
span parameter in the segmented sweep editor to 0 Hz. (
Segmented, Modify, Edit, Span
The minimum number of sweep points in zero span varies with
NOTE
software revision:
software Revision
≤ A.03.03
A.04.xx
≥ A.05.00
Zero Span sets
NOTE
mode.
Changes the analyzer frequency span to the previous span setting. If
Last Span
pressed after
span that was in effect before
even if
Segmented (Off)
the recalled information.
Key Access:
Accesses menu keys that allow you to control the two-window zone
Zone
function. This function allows you to have an upper window with a
broad display of frequency and two zone markers (vertical bars) that
define the span for the lower window.
Key Access:
140
SPAN X Scale
)
Minimum # of Sweep Points in Zero Span
401 (fixed)
101
2
Signal Track (Off)
is turned off, the span setting returns to the
Signal Track
was turned on as part of
Signal Track
. The state of
Frequency, Scale Type Log Lin
SPAN X Scale
SPAN X Scale
is selected. Segments
Segmented (On)
and
FREQUENCY, Scale Type
was turned on. This is true,
Signal Track
Span Zoom
Sweep,
to linear
. Last span sets
is included in
Chapter 2