User's Manual
ARCXTEND 5.8 GHZ USER MANUAL – R1.0, ISSUE 1
Copyright 2005 Arcwave, Inc. 18
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CATV Plant
ARCXtend
Subscriber
Transceiver
Cable Modem
ARCXtend
Hub
Transceiver
CATV Upstream
Frequency
5 MHz - 42 MHz
ARCXtend Air Frequency
5258 MHz - 5342 MHz
CM Transmit
Frequency
5 MHz - 42 MHz
LAN or USB
The Downstream DOCSIS channel can mapped to any one of the available downstream
wireless frequencies. Each downstream wireless channel is down converted by the CPE to a
fixed frequency as given in Table 3-4. e
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 wireless frequency. Note that the
downstream CATV frequency may be different than the cable modem receive frequency. This
is generally not a concern as most DOCSIS systems on which there is only one DOCSIS
downstream channel on the cable network do not specify the CM receive frequency in the CM
configuration file, rather they let the CM find the downstream on its own.
Upstream Configuration
The ARCXtend upstream block diagram is illustrated in Figure 3-4. Note that the North
American DOCSIS (Version 1.0 and 1.1) QPSK or QAM upstream signal is up to 3.2 MHz wide.
DOCSIS 2.0 upstream signals can be as much as 6.4 MHz wide. All frequencies specified in
this section are the center frequency of the particular signal.
Figure 3-4: ARCXtend Upstream Block Diagram
Upstream Block Diagram
The cable modem (CM) is commanded by the downstream signal to transmit at a specific
upstream frequency between 10 MHz and 42 MHz. Any upstream channel frequency between
10 and 42 MHz will work with ARCXtend.
Referring to Figure 3-4 from right to left:
The ARCXtend Subscriber Transceiver (CPE) up converts and transmits the entire cable
upstream band.
The Hub receives only the selected wireless upstream channel. The upstream wireless channel
is centered at 5,720 MHz plus the upstream DOCSIS channel frequency: e.g. Upstream
Channel 29.5 MHz is transmitted at 5,749.5 MHz.