On the relationship between multi-channel envelope and temporal fine structure

The envelope of a signal is broadly defined as the slow changes in time of the signal, where as the temporal fine structure (TFS) are the fast changes in time, i.e. the carrier wave(s) of the signal. The focus of this paper is on envelope and TFS in multi-channel systems. We discuss the difference between a linear and a non-linear model of information-extraction from the envelope, and show that using a non-linear method for information-extraction, it is possible to obtain almost all information about the originating signal.

This is shown mathematically and numerically for different kinds of systems providing an increasingly better approximation to the auditory system. A corollary from these results is that it is not possible to generate a test signal containing contradictory information in its multi-channel envelope and TFS.