GarrettCom 4K-Series Manual De Usuario
Magnum 4K8 Switches Installation and User Guide (10/04)
27
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4.8
Power Budget Calculations for 4K-Series FPM’s with Fiber Media
Receiver Sensitivity and Transmitter Power are the parameters necessary to
compute the power budget. To calculate the power budget of different fiber media
installations using Magnum products, the following equations should be used:
OPB (Optical Power Budget) = P
installations using Magnum products, the following equations should be used:
OPB (Optical Power Budget) = P
T
(min) - P
R
(min)
where P
T
= Transmitter Output Power, and P
R
= Receiver Sensitivity
Worst case OPB = OPB - 1dB(for LED aging) - 1dB(for insertion loss)
Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/Km]
Worst case distance = {Worst case OPB, in dB} / [Cable Loss, in dB/Km]
where the “Cable Loss” for 62.5/125 and 50/125
µm
(M.m) is 2.8 dB/km,
and the “Cable Loss” for 100/140 (Multi-mode) is 3.3 dB/km,
and the “Cable Loss” for 9/125 (Single-mode) is 0.5 dB/km
The following data has been collected from component manufacturer’s (Agilent’s and
Siemens’) web sites and catalogs to provide guidance to network designers and installers.
Fiber
Port
Module
Speed,
Std.
Mode
Std.
km
fdx
fdx
(hdx)
Wave
-
length
nm
Cable
Size
µm
X’mitr
Output
P
T ,
dB
R’cvr
Sens.
P
R ,
dB
Worst
OPB,
dB
Worst*
distance
Km, fdx
Km, fdx
typical
OPB,
dB
typical*
distance
Km, fdx
Km, fdx
FPM10-
FST
10 Mb
FL
Multi-
mode
2
(2)
850
62.5/125
100/140
50/125
-15.0
-9.5
-19.5
-31
-31
-31
-31
-31
14
19.5
9.5
5
5.9
3.4
3.4
17
23.5
13.5
13.5
6
7
7
4.8
FPM10-
SST
10 Mb
FL
Single-
mode
10
(5)
1300
9/125 -30 -39 7
14
13 26
FPM-
MST, MSC
100Mb
FX
Multi-
mode
2
(0.4)
1300
62.5/125
50/125
-20
-23.5
-31
-31
9.0
5.5
2.5
2.0
14
12
5
4
FPM-SSC
100Mb
FX
Single-
mode
18+
(0.4) 1300
9/125 -15 -31 14 28
17.5 35
FPM-SSCL
Long reach
100MB
FX
single-
mode
40
(0.4)
1300
9/125 -5 -34 27 54 32.5 65
FPM-
MTRJ
100Mb
FX
Multi-
mode
2
(0.4)
1300
62.5/125
50/125
-20
-23.5
-31
-31
9.0
5.5
3.0
2.0
15.8
12.2
5.5
4.0
* Note: The use of either multi-mode or single-mode fiber to operate at 100Mbps speed
over long distances (i.e., in excess of approx. 400 meters) can be achieved
only
if the following factors are both applied:
•
The 100Mb fiber segment must operate in full-duplex (FDX) mode, i.e. the
full-duplex (factory default) setting for 100Mbps fiber ports must be used,
and
full-duplex (factory default) setting for 100Mbps fiber ports must be used,
and
•
The worst-case OPB of the fiber link must be greater than the fiber cable’s
passive Attenuation.
passive Attenuation.
(Attenuation = Cable loss + LED aging loss + Insertion loss + safety factor)