Sigma-Delta bitstream filtering in VLSI

Abstract

This paper considers the prospects for filters with analogue I/O and internal digital signal processing performed performed directly on a Sigma-Delta modulated bitstream, with potential applications to audio systems. Simulations verify equivalent 16-bit performance of a bitstream FIR filter. VLSI design is highly regular and initial evaluation indicates that bitstream filtering is a viable alternative to decimation followed by PCM filtering.