A model for signal representation at the output of the cochlea based on minimum phase signals

The authors propose a model for signal representation at the output of the cochlea based on minimum phase (MP) signals. A minimum phase signal has the property that its phase and the logarithm of its envelope are related by Hilbert transformation. Hence by retaining either the phase or the envelope the entire signal can be represented to within a scale factor. First the authors show how to convert a given signal into one that is minimum phase by suitably adding a sinewave at the band-edge of the signal. Subsequently the authors show how to recover the original signal from the minimum phase signal´s phase or envelope. With this procedure signals can be automatically scaled (automatic gain control) to lie within a given dynamic range; the authors conjecture that such a procedure may indeed be used by the cochlea to represent signals that vary in intensity over several orders of magnitude