beautypg.com

Only – GarrettCom Quad User Manual

Page 41

background image

Magnum Quad-Series Fiber Switches

Installation and User Guide (06/09)

34

www GarrettCom com

.

.

4.7

Power Budget Calculations for Quad-Series QPM’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

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]

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

(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

typical

OPB,

dB

typical*

distance
Km, fdx

QPM10-

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

14

19.5

9.5

5

5.9
3.4

17

23.5
13.5

6
7

4.8

QPM-

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

QPM-SSC

100Mb

FX

Single-

mode

18+

(0.4) 1300

9/125 -15 -31 14 28

17.5 35

QPM-
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

QPM-

MV45

100Mb

FX

Multi-

mode

2

(0.4) 1300 62.5/125

-14 -31 15 5

16 5.7


* Not
e: 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

The worst-case OPB of the fiber link must be greater than the fiber cable’s
passive Attenuation.

(Attenuation = Cable loss + LED aging loss + Insertion loss + safety factor)