Field Guide · algorithm

Also known as: channelizer, channelization

A channelizer splits a single wideband IQ capture into many narrow channels at once.1 Each output is one channel, shifted to baseband, filtered, and decimated — so one SDR can feed many decoders in parallel.

wide IQ channelizer control ch voice ch 1 voice ch 2
A channelizer fans one wide capture into many narrow channels, enabling simultaneous decodes.

Overview

Efficient channelizers use a polyphase filter bank to extract evenly-spaced channels at once. In a trunking context this is what lets GopherTrunk watch the control channel while simultaneously following the voice channels it assigns.

Sources

  1. Filter bank — Wikipedia, on polyphase filter banks used to split a band into channels. 

See also