WarpTB - Matlab Toolbox for Warped DSP (pre-release)

Aki Härmä and Matti Karjalainen

September 15 2000

Introduction

WarpTB is a MATLAB toolbox for frequency-warped signal processing. Practically any signal processing algorithm can be warped by replacing all the unit delay elements by first order allpass blocks. Frequency-warping changes the frequency resolution of the system. Using a suitable value for a warping coefficient LAMBDA, the frequency-resolution of the system approximates closely the frequency resolution of human auditory system. This makes frequency-warped signal processing techniques beneficial in many speech and audio signal processing applications.

If you need more information about frequency warping browse to our publications page http://www.acoustics.hut.fi/publications/papers.html, where you can find several papers about the topic. In particular, many of the design examples in this toolbox are related to experiments reported in [1] and [2].

WarpTB consists of a basic toolkit and a set of optional examples and sub-toolkits for specific applications. The toolbox is free and it is available at http://www.acoustics.hut.fi/software/warp.

This is a pre-release of the final package which is going to be published by Nov. 2000. Copyrights: Aki Härmä and Matti Karjalainen, Helsinki University of Technology, Laboratory of Acoustics and Audio Signal Processing, Espoo, Finland.

Toolbox

The matlab functions of the toolbox are available here. The package can also be downloaded as a GZipped Tar file, Tar file, or zip-file.

Basically, gunzip and untar (or unzip) the package, compile the MEX files, set MATLAB's path and use. Precompiled versions of MEX files for Linux and Windows are also available here. The functions included in the current version can be seen by saying:

>> help WarpTB

A number of demonstrations can be found from 'examples' directory.

Bibliography

1

A. Härmä, M. Karjalainen, L. Savioja, V. Välimäki, U. K. Laine, and J. Huopaniemi, ``Frequency-warped signal processing for audio applications,'' in AES 108th Convention, preprint 5171 (T-5), (Paris, France), Audio Engineering Society, February 2000.

2

A. Härmä, M. Karjalainen, L. Savioja, V. Välimäki, U. K. Laine, and J. Huopaniemi, ``Frequency-warped signal processing for audio applications,'' J. Aud. Eng. Soc., November 2000.