Juniper EX4300 Series Hardware Manual page 160

Table 58: Estimated Values for Factors Causing Link Loss
Link-Loss Factor
Splice
Fiber attenuation
Clock Recovery Module (CRM)
NOTE: For information about the actual amount of signal loss caused by equipment and other
factors, see your vendor documentation for that equipment.
P
2. Calculate the ( ) by subtracting (
M
P – LL = P
B M
(13 dBm) – (0.5 dBm [HOL]) – ((5) * (0.5 dBm)) – ((2) * (0.5 dBm)) – ((2 km) * (1.0 dBm/km)) – (1 dB
[CRM]) = P
M
13 dBm – 0.5 dBm – 2.5 dBm – 1 dBm – 2 dBm – 1 dBm = P
P = 6 dBm
M
The calculated power margin is greater than zero, indicating that the link has sufficient power for
transmission. Also, the power margin value does not exceed the maximum receiver input power.
Refer to the specification for your receiver to find the maximum receiver input power.
Estimated Link-Loss Value
0.5 dBm
•
Multimode—1 dBm/km
•
Single mode—0.5 dBm/km
1 dBm
LL ) from ( P
):
B
(Continued)
Sample (LL) Calculation Values
This example assumes 2 splices. Loss
for two splices:
(2) * (0.5 dBm) = 1 dBm
This example assumes the link is 2
km long. Fiber attenuation for 2 km:
•
(2 km) * (1.0 dBm/km) = 2 dBm
•
(2 km) * (0.5 dBm/km) = 1 dBm
1 dBm
M
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