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Chapter 5 455
One-Button Measurement Functions
Meas Setup (Occupied Bandwidth—OBW)
One-Button Measurement Functions
5.21.6 x dB
Enables you to specify the power level used to determine the emission bandwidth as the
number of dB down from the highest signal point (P
1
), within the occupied bandwidth
span. Frequencies f
1
and f
2
are determined as the furthest frequencies xdB below and
above P
1
, respectively. The emission bandwidth is then calculated as f
2
− f
1
as shown in
Figure 5-1.
NOTE The asterisk next to the x dB bandwidth value in Figure 5-1 indicates the
results may not have been determined with optimal analyzer settings. If
emission bandwidth is your primary interest, select Meas Setup, Max Hold.Then
change detector mode to peak by pressing
Det/Demod, Detector, Peak. Acquiring
peak data ensures accuracy of this measurement.
Figure 5-1 Occupied Bandwidth Measurement Results
NOTE The “Transmit Freq Error” displayed above is defined as the difference
between the (f
2+f1
)/2 and the tuned center frequency of the signal.
Key Path:
Meas Setup
State Saved: Saved in instrument state.
Factory Preset: –26 dB
Default Terminator: dB
Range: –100.0 dB through –0.1 dB
P1
f2
f1fff1