JOINT FILTERBANK STRUCTURES FOR INTEGRATING AUDIO CODING INTO HEARING
AID APPLICATIONS

ABSTRACT
To help develop ultra-low power wireless hearing aid products,
we investigate the integration of subband audio coding with hearing
aid applications. Both the audio coding and the hearing aid
application use subband processing, but their requirements for the
filterbanks are totally different. The hearing aid application typically
uses an oversampled filterbank to reduce the aliasing in each
subband, whereas the audio codec needs a critically sampled filterbank
for maximal coding efficiency. A joint filterbank structure is
proposed in this paper to satisfy these contradictive filterbank requirements.
With this structure, the two filterbanks are combined
into a single stereo filterbank operation, which can be efficiently implemented
on a filterbank coprocessor. This structure substantially
reduces the computation complexity, power consumption and memory
usage.