Site
Requirements
Multimode
Power
Budget
Example
of
Dispersion
Limit
Following
is
an
example
with
the
same
parameters
as
the preceding
example
but with
multimode
link
distance
of
km
PB
11.5
dB
4km
1.0
dBIkm
40.5dB
0.5
dB
0.5
dB
HOL
dB
CRM
PB
11.5
dB
4dB2dB
1.5
dB
0.5
dB
dB
PB
1.5
dB
The
value
of
1.5
dB
indicates
that
this
link
would
have
sufficient
power
for transmission
however
due
to
the dispersion
limit
on
the
link
4km
155.52
MHz
500
MHzkm
this
link
would
not
work
with
multimode
fiber In
this
case
single-mode
fiber
would
be
the
better
choice
Single-Mode
Transmission
The
single-mode
signal
source
is
an injection
laser
diode Single-mode
transmission
is
useful
for
longer
distances
because
there
is
single
transmission
path
within
the
fiber
and smear
does
not
occur
In addition
chromatic
dispersion
is also
reduced
because
laser
light
is
essentially
monochromatic
The
maximum
overload
specification
on
the
single-mode
receiver
is
14 dBm
The
single-mode
receiver
can
be
overloaded
when
using
short lengths of
fiber
because
the transmitter can
transmit
up
to
dB
The
receiver
could
be
overloaded
at
14
dB
but
no damage
will
result
To
prevent
overloading
the receiver
connecting
short
fiber
links
insert
to
10
dB
attenuator
on
the link
between
any
single-mode
SONET
transmitter
and
the receiver
SONET
Single-Mode
Power
Budget
Example
The
following
example
of
single-mode
power budget
is
of
two
buildings
11
kilometers
apart
connected
through
patch
panel
in
an
intervening
building
with
total
of
12 connectors
Length
of single-mode
link
11
km
12
connectors
Estimate
the
power budget
as
follows
PB
11.5
dB
11
km
0.5
dB/km
120.5
dB
PB
11.5
dB
5.5
dB
dB
PB2.5dB
The
value
of 2.5
dB
indicates
that
this
link
would
have
sufficient
power
for transmission
and
is
not
in
excess
of the
maximum
receiver
input
power
Using
Statistics
to
Estimate
the
Power
Budget
Statistical
models more
accurately
determine
the
power budget
than
the worst-case
method
Determining
the link
loss
with
statistical
methods
requires
accurate
knowledge
of variations
in the
data
link
components
Statistical
power
budget
analysis
is
beyond
the scope
of
this
document
For
further information
refer
to
UNI Forum
specifications
ITU-T
standards
and your equipment
specifications
2-12
Cisco
7513
Hardware
Installation
and
Maintenance
Summary of Contents for 7513 Series
Page 1: ......
Page 11: ...Cisco 7513 Hardware Installation and Maintenance ...
Page 121: ...Site Log 2 56 Cisco 7513 Hardware Installation and Maintenance ...
Page 162: ...Troubleshooting the Processor Subsystem 4 10 Cisco 7513 Hardware Installation and Maintenance ...
Page 266: ...Interface Processor LEDs B 16 Cisco 7513 Hardware Installation and Maintenance ...
Page 270: ...C 4 Cisco 7513 Hardware Installation and Maintenance ...
Page 288: ...18 Cisco 7513 Hardware Installation and Maintenance ...