Operating Basics
Measurement
Thresholds
The following table shows the default active and clear thresholds for each test
along with the maximum and minimum values for each test. The nominal
value is the normally expected value for the test.
CAUTION.
To prevent an SNMP alarm storm from overloading the Aggregator,
you should leave enough range between the Active and Clear threshold to
account for minor signal
fl
uctuations. If the error band is too narrow and the
signal has a lot of
fl
uctuations, a large number of SNMP traps will be sent to
the Aggregator.
Table 8: Alarm measurement thresholds
Test name
Active
threshold
Clear
threshold
Minimum
value
Nominal
value
Maximum
value
Channel (input) level upper threshold
-30 dBm
-32 dBm
-90 dBm
-30 dBm
-30 dBm
Channel (input) level lower threshold
-90 dBm
-88 dBm
-90 dBm
-90 dBm
-30 dBm
Full band level upper threshold
-10 dBm
-12 dBm
-50 dBm
-10 dBm
-10 dBm
Full band level lower threshold
-50 dBm
-48 dBm
-50 dBm
-50 dBm
-10 dBm
Layer A MER lower threshold
20 dB
22 db
15 dB
20 dB
37 dB
Layer B MER lower threshold
20 dB
22 db
15 dB
20 dB
37 dB
Layer C MER lower threshold
20 dB
22 dB
15 dB
20 dB
37 dB
Left shoulder lower threshold
35 dB
37 dB
15 dB
35 dB
44 dB
Right should lower threshold
35 dB
37 dB
15 dB
35 dB
44 dB
BER (Bit Error Rate) upper threshold
100,000
parts per
billion
10,000
parts per
billion
0
parts per
billion
100,000
parts per
billion
1,000,000,000
parts per
billion
PER (Packet Error Rate) upper threshold
100,000
parts per
billion
10,000
parts per
billion
0
parts per
billion
100,000
parts per
billion
1,000,000,000
parts per
billion
Carrier frequency offset upper threshold
5,000 Hz
4,000 Hz
-340,000 Hz
5,000 Hz
340,000 Hz
Mean SNR lower threshold
20 dB
22 dB
0 dB
20 dB
28 dB
Delay pro
fi
le echo
-25 dB
NA
-25 dB
-25 dB
0 dB
Compensating for an external attenuator.
If your input signal has an external
attenuator, you need to adjust the alarm thresholds to compensate for the
attenuator.
RFM220 User Manual
65
Summary of Contents for RFM220
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