CPCI PICMG 2.16 10 U
1.9
Electromagnetic Compatibility
EMC
This microcomputer packaging system is not a complete unit.
Further items need to be fitted. According to EMC standard, we
are not talking about devices. The CE symbol has therefore not to
be used.
The systems fulfill however all conditions, in order to comply, in
the developed condition, with the EMC guideline 89/336/EWG
and the low-voltage guideline 73/23/EWG. The systems are
generally equipped with power supply units which display a CE
symbol.
The selection of the A/C line filter happens considerating the limit
value curve according to EN55022 class B. In-house measuring
instruments permit a precise selection of the filters.
In order to be prepared to the interference immunity according to
EN61000-6-2, absorption measurements are accomplished by
Schroff while designing subracks and cases. These
measurements cover the frequency range from 30 MHz to 1000
MHz according to VG 95 373, part 15.
4.4 Shielding attenuation curve europacPRO
4.4.1 Measuring principle
The shielding attenuation is achieved by measuring the insertion
losses of the testpiece. First measure the field intensity level A
0
of
the receiver on no-load (fig. 2a, without case), then the field
intensity level A
1
with a case (fig. 2b). The difference gives you the
shielding attenuation. Calibrating the recever is not necessary, as
the field intensity level A
0
can be considered as a reference.
Fig. 2a
Fig. 2b
Measuring the shielding attenuation (principle).
a) Measure without testpiece,
b) Measure with testpiece.
Shielding attenuation calculation a
s
,
4.4.2 Results
Shielding attenuation in the range of 30 MHZ to 1 GHz,
Subrack europacPRO, textil contact strip
Radiation on the front panel, vertical polarisation.
a
s
= A
0
– A
1
in dB.