Comparison and implementation of a 16-bit fixed-point audio resampler

Abstract

An audio resampler is built to convert the sampling rate from 44.1 kHz to 16 kHz. An interpolator and decimator are created separately to change the sampling rate by an integer factor. The low pass filters used by the interpolator and decimator are obtained by two different approaches: namely the window method and the equiripple design. Vie performances of these two filters are evaluated in terms of 3-dB bandwidth and pass-band signal to noise ratios. The filters are implemented using the multistage interpolated FIR approach. Polyphase structures are used to further reduce the computational load. The resampler is implemented on 16-bit fixed-point simulations. The described approach drastically reduces the filter order and thus the computational cost.