Patent ID: 6208960
Filing Date: 2001-03-27
Classification: G10L

Abstract:
A method for lengthening an audio equivalent input signal, the method comprising the steps of:positioning a first chain of mutually overlapping or adjacent time windows with respect to the signal, each time window being associated with a respective window function;forming a first sequence of signal segments by weighting the signal according to the associated window function of a respective window of the first chain of windows; andsynthesising a lengthened audio signal by systematically maintaining or repeating respective signal segments of the first sequence of signal segments;identifying a signal section in the lengthened audio signal which is synthesised from one of the signal segments, referred to as a source signal segment, by maintaining and at least once repeating the source signal segment; the source signal segment substantially having no periodic component; andbreaking periodicity in the signal section caused by repeating the source signal segment bypositioning a second chain of mutually overlapping or adjacent time windows with respect to the signal section; at least some of the time windows of the second chain having a duration not equal to a duration of the source signal segment and not equal to a multiple of the duration of the source signal segment;forming a second sequence of signal segments by weighting the signal section with the associated window function of a respective window of the second chain of windows; andgenerating an audio output signal from the lengthened audio signal by shuffling signal segments of the second sequence of signal segments.