Agilent Technologies ESA Series User's/Programmer's Reference page 110

Front-Panel Key Reference
Marker
Accesses the following marker function menu keys listed below.
Function
Key Access:
Band Power
For best accuracy, set the video bandwidth to at least ten times the
NOTE
resolution bandwidth to minimize its averaging effect.
NOTE Band Power
independent of signal level and marker placement.
Marker Noise
110
,
Marker More
Indicates the power over that part of the trace between
the reference and active markers. If only one marker is
present when you press
placed at the same location as the first marker. To
reposition the markers, press
and keys. If
Span Pair
average detection is used for RBW ≥ 1 kHz, and Sample
detection is used for RBW < 1 KHz.
The repeatability of your band power marker
measurement can be impacted by the current number
of sweep points being used. If you only have a few
sweep points in the measurement band of interest, then
small changes will have a direct impact on the
measurement result. Increasing your number of sweep
points will decrease that affect and improve the
repeatability.
Key Access:
Marker
has no meaning in zero span, and the indicated value is
Reads out the average noise level, referenced to a 1 Hz
noise power bandwidth. If no marker is present, a
marker appears at the center of the display. When
Marker Noise is enabled in resolution bandwidths of
1 kHz and above, the auto coupled detector selection is
set to Average and the Avg Type is set to Power because
the trade-off between sweep time and variance of the
result is best with power Average detection. (When the
detector is selected and the amplitude scale is
Average
linear, the fastest sweet time is 8 milliseconds.) In
resolution bandwidths < 1 kHz, the auto coupled
detector selection is Sample. However, the Marker
Noise function generates appropriately corrected values
for all supported detector modes. If the marker delta
function is on and the noise marker is activated and
moved to measure the noise floor, the marker readout
will display the signal-to-noise ratio.
, a second marker is
Band Power
to access
Marker
is selected,
Detector (Auto)
, ,
More Function
Delta Pair
Chapter 2