Nortel Networks 10292FA manual Mesh ring transmission distance, Point-to-point signal loss values

30Chapter 2 Calculating transmission distance

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 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-8demux loss	4.5 dB
System margin	3 dB
Fiber attenuation	.25 dB per km

Table 4 shows calculations used to determine maximum transmission distance for the point-to-point network example in Figure 11.

Table 4 Point-to-point maximum transmission distance calculations

Result	Calculation
Passive loss	mux loss + demux loss
Implied fiber loss	loss budget – passive loss – system margin
Maximum transmission distance	implied fiber loss ÷ attenuation per kilometer

Transmission distance calculation for the point-to-point network example in Figure 11:

•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

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.

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