Anritsu Site Master S332D - Chapter 5 Spectrum Analyzer Measurements; Occupied Bandwidth

Occupied Bandwidth
A common measurement performed on radio transmitters is that of occupied bandwidth
(OBW). This measurement calculates the bandwidth containing the total integrated power
occupied in a given signal bandwidth. There are two different methods of calculation de
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pending on the technique to modulate the carrier.
Percent of Power Method
The occupied frequency bandwidth is calculated as the bandwidth containing the specified
percentage of the transmitted power.
XdB Down Method
The occupied frequency bandwidth is defined as the bandwidth between the upper and
lower frequency points at which the signal level is
XdB below the peak carrier level.
Required Equipment
q
Site Master S332D
q
Portable antenna for the selected signal frequency
Procedure
Step 1. Connect the antenna to the Spectrum Analyzer connector.
Step 2.
On the Site Master, press the MODE key, use the Up/Down arrow key to select
the
Spectrum Analyzer mode and press ENTER.
Step 3.
Press the FREQ/DIST key, select the frequency for the measurement by using
Center and Span soft keys, the Start and Stop soft keys or the Signal Standard
and Select Channel soft keys.
Step 4.
Press the AMPLITUDE key and select the
Ref Level soft key to set the appropri
-
ate reference level.
Step 5. Select the Atten/Preamp soft key to set the input attenuation level to automatic,
manual or dynamic.
Step 6. Press
Preamp On/Off or Preamp Auto to activate the preamplifier manually or
automatically. The default preamplifier mode is auto.
Step 7. Press the
Back soft key to return to the previous menu.
Step 8. Select the
Scale soft key to set the scale. Choose a value from 1dB/div to 15
dB/div and press ENTER.
Step 9.
Press the MEAS/DISP key and select the
Bandwidth soft key to set the resolu
-
tion bandwidth and video bandwidth automatically or manually. Press the
Back
soft key to return to the previous menu.
Step 10. Press the
Measure soft key and press the OBW soft key. Select the measurement
method (dB Down or % of Power) by pressing the
Method soft key. The cur
-
rently selected method is shown in the lower left of the status window.
Step 11. Press the dBc or % soft keys to adjust the settings as appropriate.
Step 12. Press the
Measure soft key to initiate the measurement.
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Chapter 5 Spectrum Analyzer Measurements