Dell PowerConnect J-8216, Руководство по оборудованию

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Table 43: Estimated Values for Factors Causing Link Loss (continued)
Sample (LL) Calculation Values Estimated Link-Loss Value Link-Loss Factor
This example assumes 5 connectors.
Loss for 5 connectors:
5(0.5 dBm) = 2.5 dBm
0.5 dBm Connector
This example assumes 2 splices. Loss for
two splices:
2(0.5 dBm) = 1dBm
0.5 dBm Splice
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
• Multimode—1 dBm/km
• Single mode—0.5 dBm/km
Fiber attenuation
1 dBm 1 dBm 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.
2.
Calculate the (
P
M
) by subtracting (
LL
) from (
P
B
):
P
B
– LL = P
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
M
P
M
= 6 dBm
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.
Related
Documentation
Calculating the J-EX8200 Switch Fiber-Optic Cable Power Budget on page 91
•
•
Optical Interface Support in J-EX8200 Switches on page 51
•
Understanding J-EX8200 Switch Fiber-Optic Cable Signal Loss, Attenuation, and
Dispersion on page 78
93
Chapter 7: Planning Power Requirements