Juniper SRX5400 - Page 163

•
Higher-order loss = 0.5 dB
•
Clock recovery module = 1 dB
The power margin (P
M
) is calculated as follows:
P
M
= P
B
– LL
P
M
= 13 dB – 2 km (1.0 dB/km) – 5 (0.5 dB) – 2 (0.5 dB) – 0.5 dB [HOL] – 1 dB [CRM]
P
M
= 13 dB – 2 dB – 2.5 dB – 1 dB – 0.5 dB – 1 dB
P
M
= 6 dB
The following sample calculation for an 8 km-long single-mode link with a power budget (P
B
) of 13 dB uses
the estimated values from Table 44 on page 163 to calculate link loss (LL) as the sum of fiber attenuation
(8 km @ 0.5 dB/km, or 4 dB) and loss for seven connectors (0.5 dB per connector, or 3.5 dB). The power
margin (P
M
) is calculated as follows:
P
M
= P
B
– LL
P
M
= 13 dB – 8 km (0.5 dB/km) – 7 (0.5 dB)
P
M
= 13 dB – 4 dB – 3.5 dB
P
M
= 5.5 dB
In both examples, the calculated power margin is greater than zero, indicating that the link has sufficient
power for transmission and does not exceed the maximum receiver input power.
RELATED DOCUMENTATION
Connecting the SRX5400 Services Gateway to a Network for Out-of-Band Management | 195
Connecting the SRX5400 Services Gateway to a Management Console or an Auxiliary Device | 193
164