R3267 Series Spectrum Analyzer Operation Manual (Vol.1)
2.3.5 Measuring the Occupied Bandwidth (OBW)
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2.3.5
Measuring the Occupied Bandwidth (OBW)
This section describes how the occupied bandwidth of the digital modulation signal used in PDC and so
on is measured.
This function allows you to set the ratio (of the occupied bandwidth to the total power) to a range between
10.0% and 99.8%. The factory default is 99%.
Measurement conditions: The unit used for the measurement must be usable with PDC and must output
a frequency of 940.05 MHz, a level of +10 dBm and a specified bandwidth of
26 kHz.
Use appropriate parameter values to make the measurements shown below.
CAUTION:
1.
The maximum amount of power that can be input to the analyzer is 30 dBm (1 W). When measuring a signal
power whose value exceeds this limit, connect an external attenuator so the power cannot exceed 30 dBm.
2.
To reduce occupied bandwidth measurement error, use the instrument under the following conditions.
• Set the reference level so that the modulation signal level is 50 dB higher than the noise level of the spec-
trum analyzer.
• The optimum span is approximately three times the occupied bandwidth.
• Set the resolution bandwidth to less than 3% of the specified bandwidth.
• The trace detector must be set up according to the specifications of the measurement object.
Setup
1.
Connect the unit under test as shown in Figure 2-93.
Figure 2-93 Setup for Measuring the Occupied Bandwidth
Power on
2.
Turn the analyzer and the unit under test power on.
Setting the unit under test
3.
Activate the signal output for the unit under test.
Initialization
This resets the current settings to the factory defaults or user-defined presets.
