Shape invariant time-scale modification of speech using a harmonic model

A new and simple approach to shape invariant time-scale modification of speech is presented. The method based upon a harmonic coding of each speech frame operates entirely within the original sinusoidal model and makes no use of “pitch-pulse onset times” used by conventional algorithms. Instead, phase coherence, and thus shape invariance, are ensured by exploiting the harmonic relation existing between the sine waves to cause them to be in phase at each adjusted frame boundary. Results suggest this approach to be an excellent candidate for use within a concatenative text-to-speech synthesiser where scaling factors typically lie within a range well handled by this algorithm