ARX-LF-based source-filter methods for voice modification and transformation

Two ARX-LF-based source/filters models for speech signals are presented. A robust glottal inversion technique is used to deconvolve the signal into an excitation component and a filter component. The excitation component is further decomposed into an LF part and a residual part. The first model, referred to as the LF-vocoder, is a high quality vocoder that replaces the residual part with modulated noise. The second model uses a sinusoidal harmonic representation of the residual signal. The latter does not degrade the signal during analysis/synthesis and provides higher quality for small modification factors, while the former has the advantage of being a compact, fully parametric representation that is suitable for low-bit-rate speech coding as well as parametric speech synthesis applications.