Intensity-weighted average of instantaneous frequency as a model for frequency discrimination

The intensity-weighted average of instantaneous frequency (IWAIF) is developed as a model to predict listener performance in tasks primarily requiring frequency discrimination. IWAIF is closely related to the envelope weighted average of instantaneous frequency (EWAIF) model proposed by Feth for similar tasks. The primary difference is that the IWAIF model uses intensity (envelope squared) as the weighting function instead of the envelope. The advantages of IWAIF over EWAIF are that (a) it has a convenient frequency domain interpretation; and (b) it is much simpler to compute than the EWAIF. The IWAIF is the "center of gravity" of the energy spectral density function of the signal.