User's Manual

ARCXTEND USER MANUAL – R1.4, ISSUE 4
Copyright 2005 Arcwave, Inc. 19
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CATV Plant
ARCXtend
Subscriber
Transceiver
Cable Modem
ARCXtend
Hub
Transceiver
CATV Channel
EIA Channels 7 - 134
90 MHz - 855 MHz
ARCXtend Air Frequency
5729 MHz - 5843 MHz
CM Receive Frequency
429 MHz - 543 MHz
LAN or USB
Channel Plan
Downstream Configuration
The ARCXtend downstream block diagram is illustrated in Figure 3-3. Note that the North
American DOCSIS 64 QAM or 256 QAM downstream signal is 5.25 MHz wide and is transported
within a standard 6 MHz wide channel throughout the CATV plant and the ARCXtend system. All
downstream frequencies indicated are the center frequency of the 6 MHz wide channel.
Figure 3-3: ARCXtend Downstream Block Diagram
Downstream Block Diagram
The DOCSIS cable modem downstream channel on the CATV plant is already established in the
working cable modem system. At the time of installation the ARCXtend Hub is automatically
configured to the CATV downstream channel. Any EIA channel between 7 and 134, inclusive, may
be utilized. Table A-3 in Appendix A provides a list of these channels and their corresponding
center frequencies.
The downstream output of the ARCXtend Hub is the over-the-air frequency in the range of 5729
MHz through 5843 MHz. Any frequency in this range can be chosen from Table 3-4, which
determines the corresponding cable modem receive frequency. Note from the table that the cable
modem downstream receive frequency is always [air frequency – 5300 MHz]. The ARCXtend
standard downstream air frequencies were chosen to ensure that the corresponding cable modem
downstream receive frequencies are centered on standard EIA CATV channels to enable the
fastest possible cable modem downstream scan.
In summary, any CATV downstream channel may be employed as input into the Hub, and any
specified air frequency between 5729 and 5843 MHz may be chosen, but the cable modem receive
frequency (channel) is determined from the air frequency only. Note that the downstream CATV