MULTIBIT CASCADE SIGMA-DELTA MODULATOR FOR HIGH-SPEED A D CONVERSION WITH REDUCED SENSITIVITY TO DAC ERRORS/

The authors present a Sigma Delta modulator (Sigma Delta M) which comb ines single-bit and multi-bit quantisation in a cascade architecture t o obtain high resolution with a low oversampling ratio. It is less sen sitive to the nonlinearity of the digital-to-analogue (DAC) than those previously reported, thus enabling the use of very simple analogue ci rcuitry with neither calibration nor trimming required.