A low-power digital filter for decimation and interpolation using approximate processing

This low-pass filter implements approximate processing for decimation and interpolation in oversampled data converters. Included in an experimental circuit are a pair of decimation filters and two pairs of interpolation filters in a single-chip multimedia audio system. Total power for these filters is 86.4 mW with 5 V power supply when the full order of the filters is used. Power is reduced by 36% for decimation and 17% for interpolation when approximate filtering is enabled.