As defined by 3GPP TS 34.121 section 5.8 Occupied Bandwidth (OBW) is the bandwidth containing 99% of the total integrated power of the transmitted spectrum, centered on the assigned channel frequency. The test set allows the percentage of total integrated power to be adjusted from 70.0 to 99.0%.
First, the total power found in the measured frequency range is calculated. Then, starting at the lowest frequency in the range and moving upward, the power distributed in each frequency is summed until this sum is 0.5% of the total power. This gives the lower frequency value. Next, starting at the highest frequency in the range and moving downward, the power distributed in each frequency is summed until 0.5% of the total power is reached. This gives the upper frequency value. The bandwidth between the 0.5% power frequency points is the occupied bandwidth.
This measurement should be calibrated using the Calibrate Measurements function (see CALibration:MEASurements? ) when the temperature has changed by ± 10° C or more since the last calibration. If this situation exists, the integrity indicator value is changed to 19 and a message is displayed indicating "Uncalibrated Due to Temperature".