Time-scale modification of complex acoustic signals

A new approach is introduced for time-scale modification of short-duration complex acoustic signals to improve their audibility. The technique constrains the modified signal to take on a specified spectral characteristic while imposing a time-scaled version of the original temporal envelope. Both full-band and subband representations of the temporal envelope are considered. In the full-band case, the modified signal is obtained by appropriate selection of its Fourier transform phase. In the subband case, using locations of maxima in the subband temporal envelopes, the phase of each bandpass signal is formed to preserve events in the envelope of the composite signal. The approach is illustrated by application to synthetic and actual short-duration acoustic signals consisting of closely spaced and overlapping sequential time components.<>