channelizer

Channelizer is a device or software component that partitions a wideband signal into multiple narrower channels for independent processing. By decomposing spectral content, a channelizer enables parallel analysis, filtering, or demodulation of individual channels while preserving overall data flow.

Common implementations include polyphase filter banks and FFT-based channelizers. A polyphase approach uses a set of analysis filters and a decimator to produce multiple subbands with reduced computational load. An FFT channelizer uses an N-point FFT to separate the input spectrum into N channels, optionally followed by channel selection and downconversion. In both cases, optional guard bands or windowing may improve isolation between channels and reduce aliasing.

Applications include software-defined radio, where many user channels share a spectrum; digital broadcasting and spectrum monitoring; radar and electronic warfare systems; and radio astronomy, where spectral channels are analyzed for emission lines or transient events.

Key parameters include the number of channels, channel bandwidth, center frequencies, sample rate, latency, and the required stopband attenuation. Performance depends on filter bank design, polyphase implementation, and hardware resources. Channelizers may operate in real time on FPGA or DSP hardware, or run as software-defined components in general-purpose CPUs.

Examples of software environments with channelizer functionality include GNU Radio and MATLAB/Simulink toolboxes; hardware implementations are common in SDR front-ends and embedded systems. See also filter bank, digital downconverter, and spectrum analyzer.