An interference-free representation of instantaneous frequency of periodic signals and its application to F0 extraction

An interference-free representation of the instantaneous frequency of constituent harmonic components of periodic signals is introduced. The power weighted average instantaneous frequency of a band-pass filter yields this property when the effective passband of the filter covers up to two harmonic components and the two windows used in averaging are separated by a half pitch period. The proposed representation eliminates the abrupt changes found in usual instantaneous frequency representations and is applicable to any periodic signals consisting of multiple harmonic components. An F0 extractor of voiced sounds based on this representation is introduced as an example of prospective applications.