Nortel Networks 10292FA - Manual (Page 32)

32 Chapter 2 Calculating transmission distance
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Table 5 shows typical loss values that can be used to calculate the transmission
distance for the mesh ring network example in Figure 12 .
Table 6 shows the calculations used to determine maximum transmission distance
for the mesh ring network example in Figure 12 .
Transmission distance calculation for the mesh ring network example in
Figure 12 :
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Table 5 Mesh ring signal loss values
Signal loss element value
Loss budget 30 dB
CWDM OADM insertion add loss 1.9 dB
CWDM OADM insertion passthrough loss 2.0 dB
CWDM OADM insertion drop loss 2.3 dB
System margin 3 dB
Fiber attenuation .25 dB per km
Table 6 Mesh ring maximum transmission distance calculations
Result Calculation
Passthrough nodes
Passive loss
Implied fiber loss
Maximum transmission
distance
nodes 2 –
OADM add OADM drop passthrough nodes OADM passthrough loss
× ( )
+ +
loss budget passive loss system margin – –
implied fiber loss attenuation per kilometer
÷
8 nodes 2 6 Passthrough nodes = –
1.9 dB 2.3 dB 6 nodes 2.0 dB
× ( )
16.2 dB Passive Loss = + +
30 dB 16.2 dB – 3 dB – 10.8 dB Implied Fiber Loss =
10.8 dB .25 dB 43.2 km Maximum Transmission Distance =
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