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Chapter 11 - DOCSIS Analyzer
10713 Vxx.11
Below this row, the assigned device and gateway IP-address from the DHCP server are displayed.
If the ping status switches to “finished”, the results are summarized below in statistical form
(packets sent; packets received; packets lost, calculated from packets sent and received; and the
minimum, maximum and average time to receive a response from the individual PINGs). Since
many PINGs can be sent (at most 100 packets) a detailed listing for each individual PING would
not be helpful here.
During the PING test, detailed progress information appears in the line after “Ping statistics”.
Figure 11-12 DOCSIS ping test statistics
Press
MODE
and
ENTER
to exit the PING test. This not possible until the test has completely
finished and the statistical evaluation has been displayed.
11.5
DOCSIS3.1-Analyzer
Starting from DOCSIS3.1-standard additional to the single QAM carrier modulations an OFDM
modulation is introduced. That modulation is also known from DVB-T/T2. In downstream frequency
range the bandwidth of one OFDM-channel is up to 192MHz wide. In the upstream frequency
range up to 96MHz. The OFDM technic allows a much more robust and efficient usage of the
limited channelbandwidths.
For DOCSIS 3.1 the measurement receiver can work in two different frequency ranges:
5 - 85 MHz for upstream, 111 - 1218 MHz for downstream
5 - 204 MHz for upstream, 258 - 1218 MHz for downstream
How to adjust the right frequency range refer Chapter
Definitions: The also known QAM-modulation from DOCSIS3.0 is now designated as ScQAM
(single carrier QAM), because only one carrier is modulated. In OFDM up to 8096 (8k) carriers are
used, where each carrier can also be QAM modulated.
PLC: Physical Layer Link Channel, a special range inside an OFDM channel, which contains all
neccesary data used for demodualtion. The PLC uses a robust and low modulation scheme.
For DOCSIS3.1 another hardware is used in the measurement receiver, therefore the Analyzer
usage anf functionality is different from the DOCSIS3.1-Analyzer. Each functionality can be called
with the function keys F1 to F5 instead of the MODE key. During the DOCSIS3.1 analyse the
measurement section of the screen is hiding and all parameters will be shown in the analyzer
section.
