Chapter 8: Downstream Cable Access Modules (DCAMs)
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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The channels in the spectrum window must be arranged on an evenly spaced grid. This means that once you pick the first
channel frequency on a multiple of 125 kHz, then all other channels on the same RF connector must have frequencies
separated by a multiple of 8 or 6 MHz, depending on whether Annex A or B is being used. Once the first channel is
selected, the remaining channels in the window spectrum can be added using higher or lower frequencies.
When the XD CAM is operating in Annex B, up to eight channels can be placed in a spectrum window having 13 slots that
are 6 MHz wide spaced over a total of 78 MHz, or in a spectrum window having 10 slots that are 8 MHz wide and spaced
over a total of 80 MHz. In both cases these Annex B channels are 6 MHz wide.
Figure 62:
Example of Spectrum Window with Annex B 6 MHz Frequency Grid
When operating in Annex A, all of the 1-8 XD CAM channels assigned to a given F-connector must be grouped in a
spectrum window of 80 MHz. The center frequencies of Annex A channels must be separated by integer multiples of 8
MHz. There is no requirement that the channels be in the same frequency order as their channel numbers.
