Multirate double-sampling hybrid CT/DT sigma-delta modulators for wideband applications

As the sampling frequency in modulators is upper limited by the amplifier bandwidth and power consumption, sigma-delta modulators should operate with low oversampling ratios (OSRs) in broadband applications. But, the modulator accuracy is reduced by lowering the OSR. Multirate signal processing and double-sampling have been proven appropriate techniques for preventing this effect and also lowering the power consumption in discrete-time modulators. In this paper, both of these techniques are simultaneously used to achieve power efficient hybrid CT/DT sigma-delta modulators.