10.4dB/ 0.4dB/km =26 kilometers ............................................ ( 3 - 10)
5.9dB/ 0.4dB/km =14.75 kilometers .......................................... ( 3 - 11)
3.6.4 Optical Loss Budget for 1000 Base- ZX
To calculate the maximum cable distance of 1000 Base-ZX when the
number of connections and splices are 2 and 1, respectively we do the
following.First,the optical loss budget is calculated as follows:
From the product specifications of devices in Table 3.4, it is shown the
transmitting device has a +5 to 0dbm power output and our receiving
device has a -23dB minimum sensitivity. Thenthe optical loss budget is
calculated as follows:
Maximum power budget =+5-(-23) =28dB................................ ( 3 - 12)
Average power budget =+2.5- (-23) =25.5dB.............................( 3 - 13)
Minimum power budget =+0- (-23) =23dB............................... ( 3 - 14)
Assuming that we are transmitting over a 9μm Singlemode
@1550nm fiber transmission line and we have 2 connectors and 1 splice,
our calculation looks like this:
The total of maximum power budget =28dB-(20.75dB) – (10.1dB) -3dB =23.4dB...... ( 3 - 15)
The total of average power budget =25.5dB-(20.75dB) – (10.1dB) -3dB =20.9dB....... ( 3 - 16)
The total of minimum power budget =23dB-(20.75dB) – (10.1dB) -3dB =18.4dB........ ( 3 - 17)
We then take each of these total and divide it by 0.3dB/km (taken from
TIA/EIA Loss Estimates table 3.3), so
23.4dB / 0.3dB/km = 78 kilometers (the maximum total cable distance in 1000Base-ZX).. ( 3 - 18)
20.9dB/ 0.3dB/km = 69.6kilometers ............................................................. ( 3 - 19)