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7.1.3 Test Setup
7.1.4 Guidance on a
preliminary
Measuring
Procedure
7-4
Applications
Fig. 7-2. shows an example of test setup for RFI voltage measurement.
The DUT is placed 0,4 m from an horizontal or vertical earthed conducting
surface of at least 2 m x 2 m in size.
A table top DUT is placed 0,8 m from the LISN and at least 0,8 m from any
other earthed conducting surface. If the measurements are made in a
shielded room, the DUT shall be placed 0,4 m from one of the walls of the
room.
The LISN shall be bonded to the reference conducting surface.
A Floor standing DUT is placed 0,1 m above an horizontal earthed
conducting surface of at least 2 m x 2 m in size. This size shall be
exceeding by at least 0,5 m the projection of the DUT on the conducting
surface. The power cable should be 1m long; longer cable should be
centrally bundled for at least 40 cm.
DUTs without a PE (Protective Earth) conductor and manually operated
DUTs shall be measured in conjunction with an auxiliary screen or an
"Artificial Hand", as duly specified in the relevant standards.
All the details and information on the test setup are written on the latest
version of the applicable Standard.
A step-by-step example of a conducted test manually performed is the
following:
1. Switch ON the PMM 9010 and enter in Sweep Mode pressing the
relevant button;
2. Select Display and then 120dB; Reference Level should be between
110 and 135 dBµV; press Esc;
3. Touch the Measure key, then Freq and A+B Band;
4. Then Level, Input and set the Minimum Attenuation to 10 dB and the
Attenuation is automatic; press Esc;
5. Select Misc, Presel and Pulse Limiter to enable the preselction and
the protection of the input from voltage spikes; press Esc;
6. Enter in the Detector menu and select Peak; press Esc two times;
7. Connect a LISN or any other suitable transducer to the RF input,
selecting the proper phase/line whenever applicable;
8. With the EUT switched OFF touch Exec Sweep and wait until the first
scan has been finished;
9. Carry out an overview of the whole spectrum and check the by
executing a pre-measurement with peak detector that the ambient RF
disturbances are at least 20 dB below the desired emission levels;
10. If the ambient noises are low enough continue to the next step,
otherwise take all the necessary steps to reduce the ambient
disturbances (e.g. go to a shielded room, etc.);
11. Switch ON the EUT and then Measure, Exec Sweep again and wait
until the scan has been finished;
12. Enter in the Display menu and adjust the Dynamic Range and the
Reference Level to the most convenient visualization;
13. If the results are satisfactory select Marker, Peak and then either
Analyzer or Tune to enter respectively in Spectrum Mode or in Manual
Mode and deeply investigate the highest signals;
14. If the results of the scan need to be refined, select a Limit, if
appropriate, and then Measure, Level and Smart Detector (if a limit
has been loaded);
15. In the Smart Detector menu check the best combination among those
listed; enter a Margin, if needed; press Esc;
16. Exec Sweep again and repeat from step #12.
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