FILTER BANK SYSTEM FOR HEARING AIDS

The object of the invention is to make sub-band processing in hearing aids less computationally intensive. For this purpose a filter bank system comprising an analysis filter bank (AFB) for decomposing an input signal into sub-band signals, a processing device for amplifying at least one of the sub-band signals, and a synthesis filter bank (SFB) for combining the processed sub-band signals into an output signal is provided. The sub-band signals are oversampled and downsampled compared to the input signal. The stopband attenuations of the individual filters of the AFB and SFB are at least as high as a predefined signal-to-noise ratio increased by an attenuation value which is a function of the oversampling factor, the downsampling factor and possibly the gain. The magnitude frequency response of the SFB is approximately matched to the magnitude frequency response of the AFB.