have two groups, group 1 for output 0/1, group 2 for output 2/3.
The analysis of signal measured.
configuration of EQ and ATT
Signal of group 1
Signal of group 2
can find the level of DOCSIS channel of group 2 is 5db, below the level of
group 1 and the attenuation of group 1 is 3db the attenuation of group 2 is
the DOCSIS channel output of group 2 is 8db bellow the output of group1.
this DOCSIS channel is not ok too.
output of group is abnormal for all frequency, but for high frequency the
output is more bad.
The analysis of rf-power-monitor.
order to confirm our conclusion, we shutdown optical- receiver and reconfigure
the DOCSIS channel from frequency 250MHZ to 826MHZ.
The new configuration of DOCSIS channel
The new configuration of EQ and ATT
configure the same ATT and EQ of group 1 and group 2, and the operation ATT and
EQ is 3db and 18db too.
The output level of group 1 and group 2
measured the output level of group 1 and group 2 with command bellow, and
create the output graph.
graph of 2 group:
EQ of group is abnormal, but the configuration and status of EQ is OK, so, we
confirm hardware broken.
confirm the hardware of this device is damaged. And the trouble spots is EQ
chip or the circuit around EQ chip of group 2.