Sine-wave based PSOLA pitch scaling with real-time pitch marking

The sinusoidal system was reconfigured to use pitch synchronous overlap-add (PSOLA) synthesis so that pitch shifting could be achieved by moving the sine-wave parameters to the pitch-shifted synthesis frames. This, in turn, led to a pitch-marking technique based on the sine-wave phases that required no forward-backward searching for epochs, resulting in real-time pitch scaling. Having access to the sine wave amplitudes led to realistic re-shaping of the vocal tract characteristic, hence the system is well suited for real-time pitch scaling and vocal tract modification of speech.