Nortel Networks 10292FA - Manual (Page 30)

30 Chapter 2 Calculating transmission distance
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Table 3 shows typical loss values that can be used to calculate the transmission
distance for the point-to-point network in Figure 11 .
Table 4 shows calculations used to determine maximum transmission distance for
the point-to-point network example in Figure 11 .
Transmission distance calculation for the point-to-point network example in
Figure 11 :
•
•
•
Mesh ring transmission distance
The transmission distance calculation for the mesh ring configuration in Figure 12
is similar to that of the point-to-point configuration with some additional loss
generated in the passthrough of intermediate CWDM OADM nodes.
Table 3 Point-to-point signal loss values
Signal loss element value (dB)
Loss budget 30 dB
CWDM OMUX-8 mux loss 3.5 dB
CWDM OMUX-8 demux loss 4.5 dB
System margin 3 dB
Fiber attenuation .25 dB per km
Table 4 Point-to-point maximum transmission distance calculations
Result Calculation
Passive loss
Implied fiber loss
Maximum transmission distance
mux loss demux loss +
loss budget passive loss system margin – –
implied fiber loss attenuation per kilometer
÷
3.5 dB 4.5 dB 8.0 dB Passive Loss = +
30 dB 8 dB – 3 dB – 19 dB Implied Fiber Loss =
19 dB .25 dB 76 km Maximum Transmission Distance =
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