Design of FRM-Based Nonuniform Filter Bank With Reduced Effective Wordlength for Hearing Aids

This paper presents a design method for frequency response masking (FRM)-based nonuniform filter bank with reduced effective wordlength. Instead of designing prototype filters separately, we propose to model the filter bank design problem as a nonlinear programming problem and jointly design the prototype filters in the FRM structure. Moreover, in this work, all the filters are designed directly in the finite wordlength space, such that they can be directly implemented using efficient fixed-point arithmetic without any quantization. By simultaneously considering all the subband constraints during optimization, the proposed method is able to guarantee the desirable stopband attenuation for all subbands and achieve optimal effective wordlength (EWL) for the coefficients, reducing the hardware complexity for very large-scale integration (VLSI) implementation. Experimental results show that the hardware complexity of filter banks can be reduced without sacrificing the audiogram compensation performance for hearing aid applications.