Physical Measurements (Level, Mer) - Viavi OneExpert ONX CATV 620 Quick Start Manual

Physical Measurements (Level, MER)

✓ MER 2 percentile
shows how
well 98% of the subcarriers are
working and filters out
underperforming ones that LDPC
error correction will likely clear up.
THINGS TO CHECK:
Avg level, variable: >-6 dBmV recommended
Avg MER, variable: >36 dB recommended
MER at 2 percentile:
MER standard deviation:
OFDM Avg power must be within range. Good
MER and low noise enable higher modulations.
>35dB
>35 dB recommended
<2 dB recommended
© 2017 Viavi Solutions, Inc. | Viavi Confidential and Proprietary Information
MER Avg
MER
Std Dev
MER
<2dB
PCTL
2%
42 dB
CM Minimum CNR/MER
Performance in AWGN
Channel Up to 1 GHz
Modulation CNR(dB)
4096 41.0
2048 37.0
1024 34.0
512 30.5
256 27.0
128 24.0
64 21.0
16 15.0
MER
Min P
6AVG
dBmV
-6
-9
-12
-12
-15
-15
-15
-15
81