Methods and systems for processing a single sub-channel that includes two
or more combined channels. Using intermediate frequency sub-sampling, two or more
channels from a broad band signal are combined into a single sub-channel for further
analog and digital processing. Each of the two or more channels is down converted
to an intermediate frequency, filtered to remove certain undesired channels, and
combined such that the two or more channels are adjacent to each other. A digital
representation of the sub-channel is produced from the combined intermediate frequency
channels. Each channel within the digital representation is down converted to baseband,
and the in-phase and quadrature components are separated from each other. Compared
to one direct down conversion technique, intermediate frequency sub-sampling as
described in the application may reduce the number of analog to digital converters
and control amplifiers used in analog processing by a factor of four.
