Chapter 11 - DOCSIS Analyzer
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11.5.3
Docsis 3.1 downstream analyze
The Downstream-Analyze window will be called with the function key
DOWNSTREAM
.
Figure 11-15 Downstream Analyze Windows with OFDM infos
Each bar indicates one downstream channel. With the arrow keys ←/→ you can choose the
desired channel. The actual selected channel is marked in red. In the function key menus are more
detailed downstream analyzer functions available, depending on the modulation scheme (ScQAM,
OFDM).
Each downstream channel has its own identification number (Id), which is shown behind the
specific frequency (middle frequency). In Figure 11-15 is an example of an OFDM downstream
channel.
•
OFDM: amount of OFDM-carrier in 1000 (4k = 4096) and the active used bandwidth in MHz
•
level is the average over the complete bandwidth
•
MER from the PLC and as average over the complete OFDM channel
•
frequency range of PLC (the PLC is a 6MHz wide channel inside the OFDM cahnnel and
contains the demodulation informations)
•
Package Errors: amout of the not correctable packtes inside the datastream
Parameters of a ScQAM carrier are the same as used in DOCSIS-3.0-Analyzer (refer Chapter
11.4.3.1 - Downstream analysis). The downstream channel load works only at the ScQAM carrier,
which is used for tuning.
11.5.3.1
PLC parameter
With the menu item
PLC PARAM
you can show an information list of the selected OFDM
downstream carrier. The list has more subpages, which can be switched with the F-keys
<<<
and
>>>
.
The section OCD (OFDM-Channel Descriptor) contains all informations about demodulation for the
reciever side. The futher sections contains the DPD (Downstream-Profile-Descriptor) informations.
The measurement receiver only shows the first four profiles.
With the F-key
BACK
you can leave the list.
