Calculating The Ex Series Switch Fiber-Optic Cable Power Budget; Calculating The Ex Series Switch Fiber-Optic Cable Power Margin - Juniper EX4600 Series Hardware Manual

EX4600 Switch Hardware Guide
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Calculating the EX Series Switch Fiber-Optic Cable Power Budget

Related
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Calculating the EX Series Switch Fiber-Optic Cable Power Margin

76
of component attenuation, power penalties (including those from dispersion), and a
safety margin for unexpected losses.
Calculating the EX Series Switch Fiber-Optic Cable Power Budget on page 76
Calculating the EX Series Switch Fiber-Optic Cable Power Margin on page 76
Calculate the link's power budget when planning fiber-optic cable layout and distances
to ensure that fiber-optic connections have sufficient power for correct operation. The
power budget is the maximum amount of power the link can transmit. When you calculate
the power budget, you use a worst-case analysis to provide a margin of error, even though
all the parts of an actual system do not operate at the worst-case levels.
To calculate the worst-case estimate for fiber-optic cable power budget (P
link:
Determine values for the link's minimum transmitter power (P
1.
sensitivity (P ). For example, here, (P
R
decibels are referred to one milliwatt (dBm).
P = –15 dBm
T
P = –28 dBm
R
NOTE: See the specifications for your transmitter and receiver to find the
minimum transmitter power and minimum receiver sensitivity.
Calculate the power budget (P
2.
–15 dBm – (–28 dBm) = 13 dBm
Calculating the EX Series Switch Fiber-Optic Cable Power Margin on page 76
Understanding EX Series Switches Fiber-Optic Cable Signal Loss, Attenuation, and
Dispersion on page 74
Pluggable Transceivers Supported on EX Series Switches
Calculate the link's power margin when planning fiber-optic cable layout and distances
to ensure that fiber-optic connections have sufficient signal power to overcome system
losses and still satisfy the minimum input requirements of the receiver for the required
performance level. The power margin (P
attenuation or link loss (LL) has been subtracted from the power budget (P
When you calculate the power margin, you use a worst-case analysis to provide a margin
of error, even though all the parts of an actual system do not operate at worst-case
) and (P ) are measured in decibels, and
T R
) by subtracting (P ) from (P
B R
) is the amount of power available after
M
Copyright © 2014, Juniper Networks, Inc.
) for the
B
) and minimum receiver
T
):
T
).
B