Patent ID: 8085960

Claim:
A filter bank system for a hearing aid, comprising: an analysis filter bank comprising a plurality of analysis filters for decomposing an input signal into sub-band signals; a processing device for processing the sub-band signals; and a synthesis filter bank comprising a plurality of synthesis filters for combining the sub-band signals into an output signal, wherein the sub-band signals are configured to be oversampled with an oversampling factor and downsampled with a downsampling factor, wherein stopband attenuations of the analysis filters are configured to be at least as high as a predefined first signal-to-noise ratio increased by a first attenuation value which is a function of the oversampling factor and the downsampling factor, wherein stopband attenuations of the synthesis filters are configured to be at least as high as a predefined second signal-to-noise ratio increased by a second attenuation value which is a function of the oversampling factor, the downsampling factor and a gain of the processing device, and wherein a magnitude of frequency response of the synthesis filter bank is configured to be matched to a magnitude of frequency response of the analysis filter bank so that a complex-valued frequency response of cascades of the analysis filter bank and the synthesis filter bank bypassing the processing device is an all-pass transfer function.