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Key Reference
Marker
The noise marker averages 5% of the trace data
values (one- half a horizontal division), centered on
the location of the marker on the frequency or time
scale. Marker noise indicates noise power density
per Hertz or noise voltage per root Hertz depending
upon the amplitude units selected. The number of
sweep points is noted in parenthesis to the right of
the sweep time in the lower right corner of the
graticule.
Note that the data values averaged will not always
be symmetrical with respect to the marker position.
If the marker is positioned within 2.5% of the
beginning of the trace (one- quarter division), the
trace data values in the first half- division will be
averaged. Similarly, if the marker is positioned
within 2.5% of the end of the trace, the trace data
values in the last half- division will be averaged.
NOTE
Do not use Marker Noise to evaluate the displayed average noise level
of the analyzer relative to the specification. Read the displayed
average noise level directly from the display or use the normal marker.
Refer to Application Note 150 for a discussion of how noise is
displayed on a spectrum analyzer.
To guarantee accurate data for noise- like signals, a
correction for equivalent noise bandwidth for each
resolution bandwidth is measured and included in
the measurement. The Marker Noise function
accuracy is optimal when the detector is set either
to Average or to Sample because neither of these
detectors peak- biases the noise.
Key access:
> Function
Marker
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