R. Smits et B. Yegnanarayana, DETERMINATION OF INSTANTS OF SIGNIFICANT EXCITATION IN SPEECH USING GROUP DELAY FUNCTION, IEEE transactions on speech and audio processing, 3(5), 1995, pp. 325-333
A new method for determining the instants of significant excitation in
speech signals is proposed. Here, significant excitation refers prima
rily to the instant of glottal closure within a pitch period in voiced
speech, The method is based on the global phase characteristics of mi
nimum phase signals, The average slope of the unwrapped phase of the s
hort-time Fourier transform of linear prediction residual is calculate
d as a function of time, Instants where the phase slope function makes
a positive zero-crossing are identified as significant excitations, T
he method is discussed in a source-filter context of speech production
, The method is not sensitive to the characteristics of the filter, Th
e influence of the type, length, and position of the analysis window i
s discussed, The method works well for all types of voiced speech in m
ale as well as female speech but, in all cases, under noise-free condi
tions only.