SA (Spectrum Analyzer) Mode
111
Several data points (or ‘buckets’) are averaged together to calculate the Noise
Marker readout. To accurately measure noise, the Noise Marker should NOT be
placed on, or too close to, a signal. The distance from a signal depends on several
factors. To know if an accurate reading is being made, move the Noise Marker
until consistent measurements are displayed in adjacent data points.
In addition, when a Noise Marker is displayed, the Detection method is
automatically switched to Average and
PAvg
is shown on the FieldFox screen.
This occurs only when Detection is set to Auto. Learn more on page 107.
With a Noise Marker present, the Res BW can be changed and the displayed noise
floor will also change, but the Noise Marker readout will remain about the same.
Noise Markers can be used like regular markers. A Noise Marker is distinguished
from a regular marker by
(1Hz)
after the marker readout value. Learn more about
regular markers on page 174.
How to measure Noise with a marker
Press
Marker
to create or select a Normal or Delta marker to use to measure
Noise.
Then
More
.
Then
Marker Function
Then
Noise ON OFF
.
Band/Interval Power Marker
A Band/Interval Power marker, unique to SA Mode, accumulates the power that
is measured over several adjacent data points (or ‘buckets’). The range of buckets
being measured is displayed with vertical posts around the marker. This Band
Span value is selectable.
This feature is very similar to a channel power measurement (page 115).
When the frequency span is set to Zero span, the marker is referred to as an
Interval marker because it averages power over a specific time interval. In this
case the range is specified as the Interval Span. Learn more about Zero span
measurements on page 99.
If the Detection method and Averaging type are set to Auto when you enable a
Band/Interval Power marker, the Detection method will change to Average
(RMS) and Averaging type will change to Power average. Other Detection
methods or Averaging type settings will usually cause measurement inaccuracy.
Learn more about Detection method on page 107, and Averaging Type on page
106.
Summary:
In Zero span, an Interval Power Marker yields the
average power
over the
specified time interval.
In non-Zero span, a Band Power Marker yields the
total power
over the
specified frequency range.
How to measure Band/Interval Power with a marker
Press
Marker
to create or select a Normal or Delta marker to use to measure
Band/Interval Power.
Then press
More