Cisco 7513 Hardware Installation And Maintenance Manual page 75

Site
Requirements
Power
To
design
of
light
the receiver
depends
Attenuation
common
The
following
multimode
Chromatic
wavelengths
Modal
the fiber
Attenuation
chromatic
dispersion
dispersion
fiber-optic
Table
Attenuation
Dispersion Limit
The
product
Mflzkm
500
Approximating
LED
The
each with
dispersion
and
being
multimode
minimum
of the
all
The power
equation
PB
PB
PB
The power margin
follows
PM
the
If
7513
2-10 Cisco Hardware
Budget
data link
efficient
an
optical
available attenuation
to overcome
within
to
requires operate
on modulated
reaching
light
caused the passive
by
multimode and
both
to
single-mode
variables reduce the
transmission
spreading
dispersion
spreading of the signal
dispersion
lower
for
is
significantly
and modal
reduce
dispersion
decibels
in
penalty
and modal
losses Table
cable
2-9
Typical Fiber-Optic
Single-Mode
dB
0.5
No
limit
of bandwidth and distance must
Power
AlP
the
multimode
used for transmission
and
different
path length
mode
smear order
Higher
radiated
into the fiber
cladding
assumes
transmissions
PR
receiver
sensitivity
of an actual system
parts
PB
maximum
the
is
budget
the calculation of the
lists
PR
PT
-30
dBm
18.5
dBm
dB
11.5
calculation
is derived
LL
PB
power margin
is positive
as
and Maintenance
Installation
evaluate the power budget
and
in the link
optical
its
specifications Proper
the receiver with
enough power
media components
cables
transmission
of the signal transmitted
light
power
of the signal time because
in
time because of the
in
media For multimode
than for other
fiber
optical
the available of the system
power
The power
the data
lost
over
2-9 the of attenuation
lists factors
and
Link Attenuation
Dispersion
Multimode
dB/km
1.0
MHz/km1
500
be than
less
Margin
source creates multiple propagation
light
time requirement cross the optical fiber causing
to
HOL
from
loss
results
light
worst-case estimate
minimum
transmitter
power
The
worst-case
analysis provides
the worst-case
will at
operate
amount
of
power
possible
power budget
from power budget and
the
work
the link
rule will
The power budget amount
the
is
minimum
exceed
the
to
power
of an data
operation optical
be demodulated
to
correctly
and connectors
cable
splices
the receiver
to in
of
of the different
speeds
light
modes
different propagation
transmission
combined
the
by
the sum of the
link is
component
and
for typical
limit
dispersion
Limits
of light
paths
signal
LED
from the entering the
PM
of for
power margin
PT LL
maximum
link
loss
of error although
margin
levels
The
transmitted
following
the link loss
subtracts
that
link
is
in
fiber
and
not
as