Hybrid pulse width modulation/sigma-delta modulation powerdigital-to-analogue converter

摘要

A new digital signal processing technique is presented for powerndigital-to-analogue converters which offers high linearity and ansubstantial reduction in clock frequency compared to conventional pulsenwidth modulation converters. The basis of the technique is to groupntogether pulses from the output of a single bit sigma-delta modulator. Anmodel is derived which shows that the system output is essentially anpulse width modulated sequence. Noise and distortion are introduced bynthe pulse grouping but are considerably reduced using noise shapednfeedback around the pulse grouper. Simulation results are presentednwhich validate the model and indicate the performance of the techniquenwith ideal and nonideal output stages