Conducted noise measurements (pre-compliance test)

AN2840

14/19

5

Conducted noise measurements (pre-compliance

test)

Figure 18 and Figure 19 provide the results of the conducted emission pre-compliance

average detection. For conciseness, only the measurements of the worst line wire are

reported. The measurements show a good margin with respect to the limits stated in the

EN55022 CLASS-B specifications.

In comparing figures 18 and 19, it is worth noting that the VIPER17HN frequency jittering

feature makes it possible to spread the switching frequency harmonics spectrum and reduce

the peak values. This is especially evident in the average measurement where a significant

margin is achieved with respect to the limits.

graph shows even in this condition the measured noise is well below the EN55022 Class-B

limits.

Figure 18.

load CE QP measurement

Figure 19.

CE average measurement

Figure 20.

average measurement