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2-21
Making Measurements
Measurements
This sets the reference level to which the offset frequency values are compared.
• Select Ramping or Modulation (3).
• Set your Freq Offset value (4).
Figure 2-11 Output RF Spectrum Measurements
• The trace of the output RF spectrum can be viewed if you highlight View and
select Trace (5).
OutputRFSpectrum
MeasurementsUsing
a 3-Pole
Synchronously
Tuned Measurement
Filter
GSM Recommendation 11.10 and 11.20 set the requirements for the out-of-channel
performance of base station and mobile station transmitters with the Output RF
Spectrum specification. The specification calls for the measurement of transmitted
energy at several offsets from the carrier frequency. Two types of measurements are
required:
• Check the interference due to modulation.
• Check the interference due to ramping of the signal amplitude (switching
transients).
Limits are specified for each type of measurement at specified frequency offsets.
The GSM specified limits are based on a 5-pole synchronously tuned measurement
filter.
5
2,3
1,4