PDF (Thesis) - Nottingham eTheses - University of Nottingham
PDF (Thesis) - Nottingham eTheses - University of Nottingham
PDF (Thesis) - Nottingham eTheses - University of Nottingham
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CHAPTER 5: EMI MEASUREMENTS<br />
will trigger the frequency measurement for every frequency step. A RF cable must be<br />
plugged from the output <strong>of</strong> Signal Generator into the Spectrum Analyser, to feed the<br />
signal into the measuring instrument.<br />
BW: Res BW→100kHz<br />
Settings on the Spectrum Analyser<br />
AMPTD Yscale: More→YAxis unit → A<br />
Trace/Detector: Max Hold<br />
Trigger: External 1<br />
FREQ Channel: Start Freq→100kHz<br />
Stop Freq→30MHz<br />
Sweep/Control: Points→29901<br />
Input/Output: RF Input→RF Coupling→DC<br />
Settings on the Signal Generator<br />
Sweep/List: • Sweep Type→Step<br />
Frequency: 100KHz<br />
Amplitude: -10dBm<br />
• Sweep Repeat→Cont<br />
• Configure Step Sweeps: – Freq Start → 100kHz<br />
– Freq Stop→30MHz<br />
– # Points→29901<br />
– Step Dwell→40 ms<br />
Once the sweep on the Signal Generator will be complete, the Spectrum Analyser will<br />
have stored the reference, that will have to be exported to provide the vector <strong>of</strong> current<br />
vs. frequency values.<br />
Once the reference is saved, the proper measurement for the probe’s impedance has<br />
to take place. For this calibration the probe must be placed in the Current Probe Cali-<br />
bration Fixtures, as in Fig. 5.4; for this configuration four connections are needed: the<br />
usual two BNC for the 10MHz and the trigger signal, then two RF cables, one to con-<br />
nect the probe to the spectrum analyser and the other to connect the signal generator<br />
to the calibration Fixture (the metallic box visible in Fig. 5.4). Note: the other plug <strong>of</strong><br />
the calibration fixture must have a 50Ω terminator to match the cable’s impedance.<br />
The settings on the instruments are the same as before, with the only exception for the<br />
Y scale on the spectrum analyser, this parameter should now be volts (V), to read the<br />
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