This tutorial is applicable to： Toccata Plus?， Orela? 4500 Series， BelaSigna? 2xx Series This Application Note details the concepts of WOLA filterbank processing and the configuration of the WOLA filterbank coprocessor for any application. For the sake of consistency， the example of a hearing aid application is used throughout to demonstrate these concepts. However， the WOLA filterbank coprocessor can be configured creatively within it’s constraints to benefit a wide variety of audio and other applications.

　　INTRODUCTION This tutorial is dedicated to the WOLA filterbank coprocessor， which is integrated in the SignaKlara? DSP architecture. The goal of this document is to address the theoretical aspects of the WOLA filterbank， and describe the influence of each involved parameter. A good level of understanding at signal processing level is required in order for the user to properly select the appropriate filterbank configuration in a specific application. Providing basic concepts， extensive examples and illustrations， this text guides the user in this task. The tutorial is organized in the following manner： Signal Processing Aspects： ? Multirate filterbanks： the tree?structured decomposition， an introductive example ? Complex?modulation filterbank： original and complex?bandpass interpretations ? Weighted overlap?add implementation： the WOLA ? Prototype filter design Filterbank Design： Playing with the Filterbank Parameters （Using the MATLAB? WOLA Toolbox） ? Typical hearing?aid configurations （16 bands） ? Configurations with refined frequency resolution ? Overlap?add configurations （short?term discrete fourier transform） ? Performing FFTs with the WOLA filterbank ? Using special microcodes