A communications system employs digitally modulated signals operating in a band
of frequencies that is divided into two or more non-overlapping channels, with
each channel occupying no more than a predetermined maximum frequency band. A receiver
system includes a front end processor and a receiver, the front end processor being
configured to receive a data stream that represents the entire frequency band sampled
at a rate of at least twice the highest frequency within the frequency band. The
front end processor operates produces an output data stream that represents each
channel within the band, with samples for each channel within the band at a rate
that is a multiple of the symbol rate for the given channel. A receiver operates
on this data stream sequencing through the multiple channels to phase correct,
time correct, and equalize the data stream for all the constituent channels. The
communications system may be a cable television system that provides for upstream
communications through a coaxial cable from a subscriber to a "headend". Although
such a system may be a conventional system whereby a single headend may service
tens of thousands of subscribers and adhere to the DOCSIS standard for upstream
communications, the system may also employ a much more widely distributed array
of "mini-headends" that service an order magnitude fewer subscribers and that form
the boundary between coaxial and optical fiber communications.