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CHAPTER 8: FILTER REALIZATION AND EXPERIMENTAL RESULTS
I [dBµA]
100
80
60
40
20
0
−20
0.1 1 10
Frequency [MHz]
w/o filter
With filter
Limit
Figure 8.4: Comparison of Measured input CM emissions: without and with output
I [dBµA]
90
80
70
60
50
40
30
20
10
0
EMI filter (115V-400Hz to 80V-50Hz)
−10
0.1 1 10
Frequency [MHz]
w/o filter
With filter
Limit
Figure 8.5: Comparison of Measured input CM emissions: without and with output
EMI filter (115V-400Hz to 80V-100Hz)
Now the same measurements have been carried out for a standard grid input supply:
240V at 50Hz. This case will generate higher emission due to the higher voltage and
higher output current. Again Fig. 8.6 and Fig. 8.7 show the input DM emissions while
Fig. 8.8 and Fig. 8.9 illustrate the input CM ones, showing no practical difference, even
in this case.
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