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The Spectrum Application
FPC1000
60
User Manual 1178.4130.02 ─ 02
An important characteristic of a modulated signal is its occupied bandwidth (OBW). In
a radio communications system, for example, the occupied bandwidth must be limited
to enable distortion-free transmission in adjacent channels. The occupied bandwidth is
defined as the bandwidth containing a defined percentage of the total transmitted
power.
You can define a percentage between 10
% and 99
%. Numerous standards require an
occupied bandwidth of 99
%.
After entering the channel bandwidth, the R&S
FPC1000 automatically selects the
measurement parameters so that you can attain the best result.
Selecting the OBW measurement
1. Press the "Meas" key to open the measurement menu.
2. Select the "Measurement Mode" menu item to select the measurement.
3. Select the "Occupied Bandwidth" menu item.
The R&S
FPC1000 starts to measure the occupied bandwidth.
Two vertical lines show the occupied bandwidth.
The occupied bandwidth measurement shows the results and various other information
about the measurement in the diagram header.
●
Occupied bandwidth
Shows the occupied bandwidth in Hz.
●
Standard
Shows the selected
when you have selected one.
●
% power BW
Shows the
●
Channel BW
Shows the
The diagram footer shows the currently selected
and
.
..........................................................................................60
9.2.2.1
About the Measurement
The following prerequisites and settings are necessary to obtain correct results for the
occupied bandwidth.
●
Define the correct channel bandwidth.
Only the signal to be measured should be visible in the diagram. An additional sig-
nal would falsify the measurement.
●
The resolution bandwidth should be between 1
% and 4
% of the channel band-
width. This ensures that the occupied bandwidth is measured with high accuracy.
●
.
Measurements and Result Displays
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