Test Setup For 10Μs / 700Μs Impulses - Ametek CDN 118A Series Operating Manual

AMETEK CTS
4.5. Test setup for 10µs / 700µs impulses
Due to the nature of the wiring used for unshielded outdoor symmetrical
communication lines (twisted pairs), the coupling is always in common
mode. The coupling decoupling schematic is shown in Figure A.4. (IEC
61000-4-5 Ed 3.0)
Coupling via arrestors (GDT) or Avalanche breaking diodes (ABD) is the
preferred coupling method for unshielded outdoor symmetrical commu-
nication lines. The coupling network also has the task of splitting the
surge current into multiple pairs in multi-conductor cables. The internal
generator matching resistor Rm2 (25 Ω) is replaced by the Rc = 25 Ω in
the CDN 118A coupling / decoupling network.
The suggested coupling and decoupling network design and component
values may not be suitable for high speed networks as the wanted data
transmission may be degraded.
4.5.1. Test setup with 4 lines Network CDN 118A-Cx-4-1
4 Dataline setup: Two symmetrical lines (2 pairs)
Each of the 4 lines has an impedance of= 25 Ω
Bridge (grey): The 25 Ω impedance results by shorting
the 135 Ω resistors.
Bridge (CD): Connection for the built-in coupling
device (GDT/ABD) for coupling to lines
L1 to L4.
2 Data line setup: One symmetrical lines (1 pair)
Bridge (grey): The 25 Ω impedance results by shorting
the 135 Ω resistors of lienes L1 and L2.
Bridge (CD): Connection for the built-in (GDT/ABD) for
coupling to lines L1 and L2.
Operating manual V 1.00
CDN 118A series
Figure A4 IEC 61000-4-5 Ed3.0
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