Abstract:

Time-frequency representations play a central role in sound analysis and synthesis. While the most conventional methods are based on phase vocoders with uniform frequency bands, perception and physical characteristics of sound signals suggest the need for nonuniform bands. In this paper we propose a flexible design of a phase vocoder having arbitrary frequency band divisions. The design is based on recently developed nonuniform frames where here frequency warping, i.e. a remapping of the frequency axis, is employed for the design of the sliding windows, which are different for each frequency channel. We show that tight frames can be obtained with this method, which allow for perfect reconstruction with identical analysis and synthesis time-frequency atoms. The transform and its inverse have computationally efficient implementations.