System information

© 2006 Cisco Systems, Inc. All rights reserved. Cisco Confidential Presentation_ID Kirkpatrick 092509
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Link gain ? Fixed or Variable?
Upstream Dynamic Range
R-ONU (ONT) acceptable input range
CMTS
WDM
RX
ONT
Modem
0
dBmV
+20
dBmV
+40
dBmV
+30
dBmV
Home losses
-10 dB
-20 dB
Power measurement accuracy (+/- 1.5 dB)
Upstream power adjust threshold (+/- 3.0 dB)
[default is 1.0, some use 6.0]
+3 dBm
Hub setup accuracy (+/- 1.0 dB)
Factory calibration accuracy
(+/- 0.5 dB optical, +/- 1.0 dB RF)
Typical unit to unit accuracy (+/- 1.0 dB)
Amplitude Modulation has additional loss
that is a function of the link budget
Minimum upstream dynamic range:
+/- 3.0 dB CMTS power adjust
+/- 1.5 dB CMTS accuracy
+/- 1.0 dB ONT optical output accuracy
+/- 1.0 dB ONT link gain
+/- 1.0 dB Hub setup accuracy
+/- 7.5 dB = 15 dB minimum
>15 dB minimum desirable dynamic range
using any frequency plan
1:64
or
1:32
Likely additional dynamic range contributors:
 Link loss variation
– 2 dB RF for 1 dB optical in Amplitude
Modulation (not an issue with Digital or
Frequency Modulation)
 Temperature effects on laser OMI
 Future additional loading (full 5-42 MHz)