  Homomorphic analysis is a well-known method for the separation of
non-linearly combined signals. More particularly, the use of complex cepstrum
for source-tract deconvolution has been discussed in various articles. However
there exists no study which proposes a glottal flow estimation methodology
based on cepstrum and reports effective results. In this paper, we show that
complex cepstrum can be effectively used for glottal flow estimation by
separating the causal and anticausal components of a windowed speech signal as
done by the Zeros of the Z-Transform (ZZT) decomposition. Based on exactly the
same principles presented for ZZT decomposition, windowing should be applied
such that the windowed speech signals exhibit mixed-phase characteristics which
conform the speech production model that the anticausal component is mainly due
to the glottal flow open phase. The advantage of the complex cepstrum-based
approach compared to the ZZT decomposition is its much higher speed.
