645
Occupied Bandwidth Measurement
View/Display
View/Display
Accesses a menu of functions that enable you to set the view and display parameters for the current
measurement.
There is a single results view available for this measurement. For more details, and samples of screen
content for each supported mode, see “Spectrum View” on page 645 below.
The following result descriptions are available:
Occupied Bandwidth
The occupied bandwidth result is f2 – f1, where f1 and f2 are calculated.
Tota l Po wer
The total power is the power integrated in the specified span setting.
Tran smit Freq Erro r
The transmit freq error (transmit frequency error) result is calculated as the difference between (f2+f1)/2
and the tuned center frequency of the signal, where f1 and f2 are calculated.
x dB Bandwidth
The x dB result is a bandwidth measured between two points on the signal which are a certain number of
dBs down from the highest signal point within the OBW Span. For example, If the ‘x dB’ parameter is
set to –26 dB, and the ‘Occupied BW Span’ is set to 10 MHz, then the maximum signal power level is
first determined from the 10 MHz wide trace sweep. Next, the two furthest frequencies below (xdb_f1)
and above (xdb_f2) the frequency of the maximum level occurrence are found where the signal level is
26 dB below the peak level. This calculation also uses linear interpolation to find the lower and upper
carrier boundary point within the width of a sweep point (the span divided by the number of sweep
points).
The x dB bandwidth is calculated to be xdb_f2 – xdb_f1.
Spectrum View
NOTE An asterisk next to the x dB bandwidth value indicates the results may not have
been determined with optimal analyzer settings. If this result (emission bandwidth)
is your primary interest, select Meas Setup, Max Hold, On. Then, change the
detector mode to Peak. Acquiring peak data ensures accuracy of the result.
For WCDMA, C2K, 1xEVDO, WIMAX OFDMA, WLAN modes: