User's Manual

6.4 <> 48.0 12.8
U/S IF
481 <> 571 529
D/S IF
ARCe ll
Subscriber
Transceiver
5729 <> 5819 5777
D/S AIR
5306.4 <> 5348.0 & 5293.6 <> 5252.0
5312.8 & 52 87 .2
U/S AIR
Modem
429 <> 519 477
D/ S I F
6.4 <> 48.0 12.8
U/S IF
Laptop computer
LAN Data
Al l Frequencies are channel center i n MHz
Upstream 1 (rcv)
Dow nst ream (Tx)
W-CM TS
Up conv ert er
44 44
Figure 4-1: Frequency Plan.
Figure 4-1 illustrates the range of frequencies and an example of one configuration of up and
down conversions. The example is:
a) The 44 MHz Downstream IF signal at the W-CMTS is upconverted to 529 MHz.
In the BSR1000W this is done internally, in the V3000W this is done externally by
the Cadco Upconverter unit.
b) The Figure shows that this upconversion could be any frequency in the range
481 to 571 MHz.
c) The Hub Transmitter modulates this new IF to the 5 GHz band. In this example,
the 529 MHz is upconverted to 5777 MHz.
d) The Subscriber Receiver downconverts example’s 5777 MHz to 477 MHz IF,
which is a standard CATV channel the modem can detect.
e) Going in the Upstream, the modem output (transmit) upstream is 12.8 MHz in
this example.
f) The Subscriber Transmitter (inside the Transceiver) up-converts this to 5312.8
MHz and to 5287.2 MHz, which goes over the air to the Hub Receiver. The
transmission is scheduled by the DOCSIS protocol, so that it does not interfere
with other modem transmission on this channel.
g) The Hub Receiver tuned to 5312.8 MHz, down-converts this to 12.8 MHz.
h) The W-CMTS Upstream port detects the 12.8 MHz upstream signal.
The Figure also shows what a spectrum analyzer would see, namely that the subscriber unit is
also transmitting at 5287.2 MHz, but to receive this, the Hub would need the Receiver tuned to
5287.2 MHz.
June 2003 Page 4-3