High speed low area OBC DA based decimation filter for hearing aids application

This brief presents a decimation filter for hearing aid application using distributed arithmetic (DA) approach. In this paper, we propose a reconfigurable offset-binary code (OBC) DA based finite impulse response (FIR) filter with a shared look-up table (LUT) updating scheme. The size of the LUTs in DA increases exponentially with the order of filters. Shared LUT based DA structure is a solution to reduce this large memory requirement for higher order filters. The proposed shared LUT updating scheme uses LUT partitioning in which coefficients are spilt into small length vectors and it ensures a drastic reduction in the size of LUTs. The proposed DA filter is synthesized on CMOS 90 nm technology using Synapsis ASIC Design Compiler. The proposed design achieves high speed at a reduced area-delay product (ADP) when compared with recent designs. The proposed architecture is implemented and tested on Virtex 5vsx95-1ff1136 FPGA and the results show that the proposed design involves less number of slices and offers high speed than existing designs. A three-stage decimation filter of hearing aids is designed with the proposed FIR filter and is implemented on the target device by Matlab simulink and Xilinx system generator.