Acoustic analysis of voiced speech with varying noise and perturbation levels

The effects of introducing varying levels of noise, jitter and shimmer to synthetic speech signals are examined; in particular, the manner in which these variations result in changes to certain measurements that are used to quantify speech are investigated. The measurements that are examined include indicators of the open phase of the glottal pulse and spectral tilt measures. Some of the spectral tilt measures are shown to provide perturbation-free measurements of noise levels in synthesised speech signals.