CDMA2000 Base Station Measurements (Option K82) R&S FSL
1300.2519.12 2.124 E-11
9. Set a PN Offset.
– In the Settings Overview dialog box select the Demodulation Settings button.
– In the PN Offset field enter 200.
Again, screen A shows the CDP measurement, screen B the result summary. In the result summary,
the Trigger to Frame result is not correct. Also, the error message SYNC FAILED indicates that the
synchronization has failed.
– In the PN Offset field enter 0
After adjusting it, the PN offset on the R&S FSL is the same as that of the signal. In the result summary
the Trg To Frame value is now shown correctly.
Fig. 2-86: Result summary of the code domain measurement with the Trigger to Frame
value
Measuring the Composite EVM
The Error Vector Magnitude (EVM) describes the quality of the measured signal compared to an ideal
reference signal generated by the R&S FSL. In the I-Q plane, the error vector represents the ratio of the
measured signal to the ideal signal on symbol level. The error vector is equal to the square root of the
ratio of the measured signal to the reference signal. The result is given in %.
In the Composite EVM measurement the error is averaged over all channels (by means of the root
mean square) for a given Power Control Group (PCG). The measurement covers the entire signal
during the entire observation time. On screen the results are shown in a diagram, in which the x-axis
represents the examined PCGs and the y-axis shows the EVM values.
Test Setup:
Connect the RF output of the Signal Generator to the RF input of the R&S FSL (coaxial cables with
N connectors).
Connect the reference input (EXT REF IN/OUT) on the rear panel of the R&S FSL to the reference
output (REF) on the signal generator (coaxial cable with BNC connectors).
Connect external triggering of the analyzer (EXT TRIG GATE) to the signal generator’s trigger
(TRIGOUT1 at PAR DATA).
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