Method and system for playing audio at an accelerated rate using multiresolution analysis technique keeping pitch constant

摘要

A signal processing unit for playing back an audio signal at an accelerated rate keeping pitch constant. The audio signal is at least one of a speech signal, a pure music or an audio signal which comprises of both speech and music signal. The signal processing unit comprises a plurality of bandpass filters with each of them receiving a first plurality of samples of the audio signal, a plurality of decimators and an adder. The plurality of bandpass filters generate a second set of plurality of samples after passing the first plurality of samples of the audio signal through each of them. The plurality of bandpass filters have different pass bands, different stop bands, and a constant Q factor. The plurality of decimators are connected to the plurality of bandpass filters and generate a third set of plurality of samples. The plurality of bandpass filters and the plurality of decimators correspond in number. The adder superimposes constituents of the third set of plurality of samples generated by the plurality of decimators. The adder outputs a fourth plurality of samples which on playing gives rise to an accelerated version of the audio signal having a pitch which is consistent with a pitch of the audio signal in a non-accelerated condition.