EMC Design for Telecom Network Equipment

1
EMC Design for Telecom Network Equipment

• First generation digital exchanges (78-91)
• - HW- and SW- modularity
• - Clock frequency lt 25 MHz
• - Analog and digital UTP(lt144 Kb/s) access
• Output lines 2 Mb/s, coaxial or STP
• Large installations (up to 40 cabinets)

2
Second generation, 1994-2001

• Open interfaces, purchased HW
• Clock frequencies lt 200 MHz
• 250 W/subrack, 25 mm PIU modularity
• External coaxial cables 2 Mb/s to 155 Mb/s
• xDSL access on UTP cables
• Internal STP cables up to 50 Mb/s
• Large systems 3-5 cabinets

3
EMI issues, large systems

• EMI specification of cabling
• individual cable assemblies (CA)
• cable harness
• EMI specification of mechanics
• individual enclosures
• array of enclosures
• EMI couplings between CA and mechanics