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99
Figure 5-25 GSM Signal Channel Power Measurement
VII. Occupied Bandwidth Measurement
This Section describes how to measure the signal occupied bandwidth using the S5105D/E/F
microwave analyzer.
1
Definition of Occupied Bandwidth
The occupied bandwidth refers to the frequency bandwidth corresponding to the total transmit power of
99% of the energy, which is centered as the center frequency of the specified channel. The occupied
bandwidth measurement of the S5105D/E/F microwave analyzer can present the measurement results
in a quick, clear and accurate manner. There are two methods for calculating the occupied
bandwidth depending on the modulation method:
a) Power percentage method:
The occupied bandwidth of the signal is obtained by calculating the bandwidth of the portion of the
frequency containing a certain percentage of the total transmitted signal power, and the percentage of
power can be set by the user.
b) Power drop XdB method:
The calculation method defines the occupied bandwidth as the distance between the two frequency
points when the signal power drops by XdB on both sides of the frequency point where the peak power
of the signal is located. The X dB of the signal power drop is set by the user.
2
Measurement Steps
Steps for measuring the occupied bandwidth using the S5105D/E/F microwave analyzer are as follows:
a) Reset the microwave analyzer to its default state:
Press
【
Reset
】
, [Default State] .
b) Set center frequency:
Press
【
Frep
】
, [Center Freq] , input the center frequency value with the numeric keys and press the
corresponding soft key to select the frequency unit.
Set the center frequency of the microwave analyzer to the frequency of the signal to be tested.
c) Set resolution bandwidth:
Press
【
BW
】
, [RBW Auto Man] to set the resolution bandwidth to the appropriate value.
d)
Set video bandwidth:
