A nonparametric method of formant estimation using group delay spectra

A novel minimum-phase group delay technique is discussed that is a nonparametric spectral analysis method possessing the ability to demerge closely coupled formants and detect weak formants. It therefore requires no assumptions concerning the underlying nature of the signal, other than that it originates from an LTI filter system. The technique provides a level of performance in formant detection normally associated only with larynx-synchronous techniques. Moreover, it is extremely easy to implement, requiring only three FFT operations per analysis frame