Image Number 3 for United States Patent #5479564.
Method and apparatus for manipulating an input signal (e.g. an audio (equivalent) signal) to obtain an output signal having a different pitch and/or duration. The method includes (a) positioning a chain of successive overlapping time windows with respect to the input signal; (b) deriving segments signals from the input signal and the windows; and (c) synthesizing the output signal by chained superposition of the segments signals. Each of the windows (except for the first window in the chain) is positioned by incrementing a position of the window from a corresponding position of a preceding window in the chain by a time interval. The time interval is substantially equal to a local pitch period for a portion of the input signal with respect to which the window is positioned. Accordingly, each of the windows of the chain (except for the first window) is positioned so that it begins at a predetermined time interval from a preceding window in the chain. The apparatus includes units for carrying out each of these processes.