Analysis
R&S
®
FSV/A3000 I/Q
Analyzer
117
User Manual 1178.8536.02 ─ 01
6.4.4
Marker Functions
Some special marker functions are available in the I/Q Analyzer application.
6.4.4.1
Measuring the Power in a Channel (Band Power Marker)
Access
: "Overview" > "Analysis" > "Marker Functions" > "Band Power" > "Band Power
Config"
or
: [MKR FUNC] > "Select Marker Function" > "Band Power"
To determine the noise power in a transmission channel, you could use a noise marker
and multiply the result with the channel bandwidth. However, the results would only be
accurate for flat noise.
Band power markers allow you to measure the integrated power for a defined span
(band) around a marker (similar to ACP measurements). By default, 5 % of the current
span is used. The span is indicated by limit lines in the diagram. The results can be
displayed either as a power (dBm) or density (dBm/Hz) value and are indicated in the
marker table for each band power marker.
Relative band power markers
The results for band power markers which are defined as
delta
markers and thus have
a reference value can also be calculated as reference power values (in dB).
For analog demodulation measurements, relative band power markers are not availa-
ble.
In this case, the result of the band power deltamarker is the difference between the
absolute power in the band around the delta marker and the absolute power for the ref-
erence marker. The powers are subtracted logarithmically, so the result is a dB value.
[Relative band power (Delta2) in dB] = [absolute band power (Delta2) in dBm] - [abso-
lute (band) power of reference marker in dBm]
The measured power for the reference marker may be an absolute power at a single
point (if the reference marker is not a band power marker), or the power in a band (if
the reference marker is a band power marker itself).
If the reference marker for the band power marker is also a delta marker, the absolute
power level for the reference marker is used for calculation.
For the I/Q Analyzer application, band power markers are only available for Spectrum
displays.
The entire band must lie within the display. If it is moved out of the display, the result
cannot be calculated (indicated by "-
-
-" as the "Function Result" ). However, the width
of the band is maintained so that the band power can be calculated again when it
returns to the display.
Marker Usage