A new cosine series antialiasing function and its application to aliasing-free glottal source models for speech and singing synthesis
This work addresses aliasing issues in speech and singing synthesis, providing a reliable basis for testing extractors and analysis methods, but it is incremental as it builds on existing models.
The authors tackled the problem of aliasing in glottal source models for speech synthesis by introducing a new cosine-series-based antialiasing function and applying it to models like Fujisaki-Ljungqvist and Fant-Liljencrants, resulting in aliasing-free excitation source signals implemented in open-source MATLAB tools.
We formulated and implemented a procedure to generate aliasing-free excitation source signals. It uses a new antialiasing filter in the continuous time domain followed by an IIR digital filter for response equalization. We introduced a cosine-series-based general design procedure for the new antialiasing function. We applied this new procedure to implement the antialiased Fujisaki-Ljungqvist model. We also applied it to revise our previous implementation of the antialiased Fant-Liljencrants model. A combination of these signals and a lattice implementation of the time varying vocal tract model provides a reliable and flexible basis to test fo extractors and source aperiodicity analysis methods. MATLAB implementations of these antialiased excitation source models are available as part of our open source tools for speech science.