180 Chapter 2
One-Button Measurement Functions
Meas Setup (Occupied Bandwidth—OBW)
One-Button Measurement Functions
Remote Command:
[:SENSe]:OBW:FREQuency:SPAN <freq>
[:SENSe]:OBW:FREQuency:SPAN?
Example: OBW:FREQ:SPAN 10 MHz
OBW:FREQ:SPAN?
2.18.6 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 (P1), within the occupied bandwidth
span. This function is an independent calculation from the OBW calculation. The x dB
Bandwidth result is also called the emissions bandwidth, or EBW. This will set arrow
markers (f1 and f2) to your specified dB value below the maximum power and compute the
total power between those arrows. Frequencies f1 and f2 are determined as the furthest
frequencies x dB below and above P1, respectively. The emission bandwidth is then
calculated as f2 − f1 as shown by the arrows indicated in Figure 2-6 (note that the diamond
markers are for the OBW function).
NOTE The asterisk next to the x dB bandwidth value in Figure 2-6 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 2-6 Occupied Bandwidth Measurement Results
P1
f1fff1 f2