Digital-Domain Dithering of Sigma-Delta Modulators Using Bit Flipping

A new technique is presented for dithering single-bit sigma-delta modulator (SDM) analog-to-digital and digital-to-analog converters (ADCs and DACs) in the digital domain. The system operates by detecting and randomizing the limit cycles repsonsible for baseband tones. The system is efficient to realize in hardware and avoids the implementation problems of analog dither required in conventional SDM ADCs.