Figure 37 Results of verification sweep (PIM vs Distance screen)
If the PIM vs Distance plot does not satisfy the above criteria, the system should be recalibrated. Simply press the CAL
button at the top of the RTF Analysis screen and follow the on-screen prompts.
If the verification sweep is still unsatisfactory after the system has been recalibrated, it is possible that your PIM Source
4.
Now examine the Return Loss vs Distance plot in standard resolution mode. The plot should consist of a single large
peak located in the range 0.0 to 0.5 metres, as shown in Figure 38. The amplitude of the peak should be somewhere
in the range 18–40 dB, depending on the iQA/iPA frequency variant. The height of the main peak above all the other
peaks on the plot should be between 30 and 40 dB.
8.5
Verifying the Accuracy of the Calibration
Before commencing an extended round of RTF measurements on the device under test, it is advisable to perform a
verification sweep to check the accuracy of the calibration. This entails performing an RTF analysis on a known device,
and making sure that the results fall within the expected range. The procedure is as follows:
1. Attach the Passive Intermodulation Source (Kaelus part no. PIS-0002A or CIS-0001A) to the Test port of the RTF
module.
2. Press the green RF ON/OFF button. The instrument will now perform a return loss sweep, followed by a PIM sweep.
3. When the measurement sweep is complete, examine the PIM vs Distance plot in standard resolution mode. The plot
should consist of a single large peak located at zero metres, as shown in Figure 37. The amplitude of the peak will
vary with iQA/iPA frequency variant, tone powers and PIM product, however, the height of the main peak above all the
other peaks on the plot should always be between 30 and 40 dB.
Operating Manual
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Passive Intermodulation and Return Loss Fault Ranging Device
48
