DECrepeater 90FS Installation and Configuration
65
Fiber-Optic Loss Budget (Cont.)
The loss budget for fiber-optic devices should include the maximum launch power
amounts as shown in Table 7.
Table 7 DECrepeater 90FS Best-Case Maximum Launch Power
Unit of
Multimode, Graded Index Fiber Size
(Microns)
Measurement
Measure
50/125
62.5/125
85/125
100/140
Maximum peak
transmit power
dBm
–12.8
–9.0
–6.8
–3.5
Maximum average
transmit power
dBm
–15.8
–12.0
–9.8
–6.5
When the DECrepeater 90FS is connected to short lengths of 85/125-micron or
100/140-micron fiber-optic cable, the connection might require additional
attenuation to prevent exceeding the –9.0 dBm peak (–12 dBm average) received
power level. To make that determination, do the following:
1. Subtract the cable’s characterized attenuation value from the value listed in
Table 7.
2. If the result of this calculation is less negative than –9.0 dBm peak (–12.0 dBm
average), connect the fiber-optic cable to the DECrepeater 90FS and mea-
sure the actual power level at the opposite end of the cable to determine
whether additional attenuation is required.
If required, attenuators (such as Fotec part number A-450-A) can be obtained from
Fotec, Inc. in Charlestown, Massachusetts, or contact other fiber-optic vendors for
an equivalent part.
Содержание DECrepeater 90FS
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