Nonlinear filtering of multiplied and convolved signals
Alan V. Oppenheim, Ronald W. Schafer, Thomas G. Stockham · Proceedings of the IEEE · 1968
An approach to some nonlinear filtering problems through a generalized notion of superposition has proven useful. In this paper this approach is investigated for the nonlinear filtering of signals which can be expressed as products or as convolutions of components. The applications of this approach in audio dynamic range compression and expansion, image enhancement with applications to bandwidth reduction, echo removal, and speech waveform processing are presented.