Variable speed reproduction of audio signal without spectral change - dividing digitised audio signal into blocks, performing transformation, and adding or omitting blocks before reverse transformation

摘要

After digitising an analogue audio signal, consecutive samples of the timing signal are divided into a series of blocks, each block containing an equal number of samples. A transformation is performed on each block, and owing to doubling or omission of blocks, the original number of blocks is changed. The modified series of blocks is converted back into a series of sample blocks by reverse transformation, and this series of blocks forms the consecutive samples of the timing signal having a different reproduction speed. The omission of blocks raises the reproduction speed, the addition of blocks reduces the speed. USE - For dubbing of synchronised audio track in film or video, for synchronising audio signals in sound studio, or for use in audio typing systems, etc..