Digital signal processing techniques for pitch shifting and time scaling of audio signals

Szymon Buś , Konrad Jędrzejewski

Abstract

In this paper, we present the techniques used for modifying the spectral content (pitch shifting) and for changing the time duration (time scaling) of an audio signal. A short introduction gives a necessary background for understanding the discussed issues and contains explanations of the terms used in the paper. In subsequent sections we present three dierent techniques appropriate both for pitch shifting and for time scaling. These techniques use three dierent time-frequency representations of a signal, namely short-time Fourier transform (STFT), continuous wavelet transform (CWT) and constant-Q transform (CQT). The results of simulation studies devoted to comparison of the properties of these methods are presented and discussed in the paper.