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Marker Function
marker.
The
Marker Fctn menu controls which marker functions are turned on and allows you to adjust setup
parameters for each function. The Marker Functions are
Marker Noise, Band/Interval Power, and
Band/Interval Density, only one of which can be on for a given marker.
If the selected marker is off, pressing Marker Fctn sets it to Normal and places it at the center of the
display on the trace determined by the Marker Trace rules. However, if the selected marker was
Off,
Marker Function Off had to be the selected function, and it remains so even after the marker is thus
turned on, although you may then change it.
Fixed marker functions
In the case of a fixed marker, it is not possible to turn on or change a band function. This is because a
Fixed marker holds the value it had when it became fixed; the trace it was on may keep on changing, so
the function value, which depends on trace data, could not be calculated on an ongoing basis.
It is possible to have a Marker Function on for a Fixed marker, in the case where a function was already
on when the marker became Fixed. In this case the function value will be retained in the marker. It is also
possible to have a Marker Function on for a Fixed marker in the case when the marker was off and was
turned on as
Fixed because Delta was pressed to create a reference marker - in which case the marker
function, marker function width, Y Axis value and marker function result that the
Delta marker had
when
Delta was pressed are copied into the Fixed marker. If Delta is pressed again, causing the fixed
reference marker to move to the delta marker’s position, the marker function, marker function width, Y
Axis value and marker function result that the
Delta marker had when Delta was pressed are again
copied into the fixed reference marker.
If a Marker Function is on for a Fixed marker, the marker’s reported value is derived by the function.
Therefore you cannot directly set the X or Y value of a Fixed marker which has a marker function turned
on. Indirect setting as detailed above or when a Peak Search is performed is allowed, as the Fixed marker
is always placed on a trace and can derive its function value from the trace at the moment when it is
placed.
Interval Markers
What is an interval marker? The band power marker computes the total power within a span in a nonzero
span. The results computation must include the RBW. The interval power marker measures the average
power across some time interval in zero span.
Interval Density is defined to be Interval Power divided by Bn. Bn is the noise bandwidth of the RBW
filter, as noted and used within the Band Power computation.
Select Marker
See “Select Marker” on page 992.
Marker Noise
Turns on the Marker Noise function for the selected marker, making it a noise marker. If the selected
marker is off, it is turned on in
Normal mode and located at the center of the screen.
When
Marker Noise is selected while in the Marker Function Off state, the Band Span or Interval
Span
is initialized to 5% of the screen width.