Method and apparatus for manipulating pitch and/or duration of a signal

An apparatus for manipulating an input signal to obtain an output signal having a different pitch and/or duration than the input signal, the apparatus comprising:

• positioning means for positioning a chain of successive overlapping time windows with respect to the input signal;
• incrementing means for determining a position of each of the windows, except for a first window in the chain, by incrementing from a corresponding position of a preceding window in the chain by a time interval which is substantially equal to a local pitch period for a portion of the input signal with respect to which that window will be positioned;
• segmenting means for deriving segment signals from the input signal and the windows, each of the segment signals being derived by weighting the input signal as a function of position in a corresponding one of the windows;
• and
• combination means for synthesizing the output signal by chained superposition of the segment signals.

A method for producing an output signal from a first signal and a second signal, the method comprising:

• overlapping the first and second signals so that a beginning portion of the second signal overlaps an end portion of the first signal, the beginning portion of the second signal beginning at a position in time relative to the end portion of the first signal which minimizes a criteria which is indicative of a transition phenomenon in the output signal;
• positioning a chain of successive overlapping time windows with respect to the first and second signals, each of the windows, except for a first window in the chain, being positioned by incrementing a position of the that window from a corresponding position of a preceding window in the chain by a time interval which is substantially equal to a local pitch period for a portion of the first signal, the second signal or a combination of the first and second signals with respect to which that window will be positioned, said incrementing thereby determining where that window is positioned;
• deriving segment signals from the first and second signals and the windows, each of the segment signals being derived by weighting the first signal, the second signal or a combination of the first and second Signals as a function of position in a corresponding one of the windows;
• and
• synthesizing the output signal by chained superposition of the segment signals.

An apparatus for producing an output signal from a first signal and a second signal, the apparatus comprising:

• overlapping means for overlapping the first and second signals so that a beginning portion of the second signal overlaps an end portion of the first signal, said overlapping means being adapted to position the beginning portion of the second signal at a position in time relative to the end portion of the first signal which minimizes a criteria which is indicative of a transition phenomenon in the output signal;
• positioning means for positioning a chain of successive overlapping time windows with respect to the first and second signals;
• incrementing means for determining a position of each of the windows, except for the first window in the chain, by incrementing from a corresponding position of a preceding window in the chain by a time interval which is substantially equal to a local pitch period for a portion of the first signal, the second signal or a combination of the first and second signals with respect to which that window will be positioned;
• segmenting means for deriving segment signals from the first and second signals and the windows, each of the segment signals being derived by weighting the first signal, the second signal or a combination of the first and second signals as a function of position in a corresponding one of the windows;
• and
• combination means for synthesizing the output signal by chained superposition of the segment signals.