pro bel Freeway Series, Руководство пользователя

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Pro-Bel equipment has been tested against the European standards EN50081-1 and -2.
In all cases, the results depended heavily on the use of the correct cables and
connectors, and their correct assembly. Precautions applicable to each common
signal type are specified below. Installation provisions must be followed in order
that compliance is maintained in service. Normal practice as regards pushing cards
fully home and ensuring that connectors are well seated is essential to good EMC
performance.
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Cable should be of good 110 W design with a foil shield, such as Canford DST. This
shield must make contact all round at the entry to the mating connector body. Pro-
Bel equipment with AES3 interfaces is fitted with 'D' type connectors and the shield is
grounded to the chassis at the point of entry. The 'D' type shield should be of the
tinned type fitted with screw-locks and with dimples on the male part. Where a
number of channels use the same connector, an overall shield is preferred in addition
to individual shields and this must also be firmly grounded at both ends.
S S e e r r i i a a l l d d i i g g i i t t a a l l v v i i d d e e o o i i n n p p u u t t s s a a n n d d o o u u t t p p u u t t s s
Cable should be good quality 75
W
design with double braided screens such as PSF1/3
or Belden 8281. Pro-Bel equipment with Digital Video ('SDI' or SMPTE 259M)
interfaces are fitted with BNC type connectors where the shield is grounded to
chassis at the point of entry. BNC plugs must be of the best quality as this type is
prone to EMC leakage if contact is not good all round the shell.
It is possible to improve the emissions caused by this leakage by using cables with
ferrite collars. This prevents leakage affecting adjacent cables in the installation
space.
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As with analogue audio the risk lies with processors within the same equipment. All
output BNCs have the shield grounded at the fixing point and most inputs. However,
some inputs have floating connectors for maintenance of common-mode rejection.
Again, only good double-screened cable such as PSF1/3 should be used.