In speech coding/synthesis this called a "source-filter" model (decompose speech production into a sound generator in the vocal folds and filter in the vocal tr

In speech coding/synthesis this called a "source-filter" model (decompose speech production into a sound generator in the vocal folds and filter in the vocal tract, and parameterize them) and it's actually older than Tukey and Cooley's rediscovery of the FFT.