Method and apparatus for adjusting the pitch and timbre of an input signal in a controlled manner

An apparatus for independently shifting the pitch and the timbre of an input signal in a controlled manner, the apparatus comprising:

• a pitch detector for determining a window length of an input signal based on the input signal
• a synchronous windower for creating a finite length spectrally smoothed signal;
• a resampler for adjusting the timbre of the finite length spectrally smoothed signal by resampling the finite lens spectrally smoothed signal at a predetermined resampling ratio thereby creating a finite length timbre adjusted signal;
• and
• a recombiner for combining the finite length timbre adjusted signal at a rate necessary to produce a desired output pitch, wherein artifacts introduced from processing the finite length spectrally smoothed signal and the finite length timbre adjusted signal are reduced.

A modified Lent shifter capable of independent timbre and pitch adjustment comprising:

• a pitch detector for measuring the period of an input signal;
• a synchronous windower for spectrally smoothing the input signal by synchronously windowing the input signal thereby creating a plurality of finite length windowed data;
• a resampling timbre adjuster for adjusting the timbre of the input signal using a predetermined resampling ratio on the plurality of finite length windowed data created by the synchronous windower within the modified Lent shifter;
• and
• a pitch adjusting recombiner for recombining the plurality of finite length windowed data at a desired rate.

An apparatus for adjusting the pitch and timbre of an input signal, the apparatus comprising:

• means for receiving an input signal;
• means for determining a window length based on the input signal;
• means for creating a finite length spectrally smoothed signal from the input signal by synchronously windowing the input signal;
• means for adjusting the timbre of the finite length spectrally smoothed signal by resampling the finite length spectrally smoothed signal at a predetermined resampling ratio thereby creating a finite length timbre adjusted signal;
• and
• means for recombining the finite length timbre adjusted signal at a rate necessary to produce a desired output pitch thereby reducing artifacts introduced by processing the finite length timbre adjusted signal and minimizing latency between receiving the input signal and producing a desired output signal.