A sigma-delta modulator topology with high linearity

A Sigma Delta modulator topology is presented which achieves high linearity by modifying the transfer function of the quantizer in the loop. It is applicable to both A-D and D-A converters. Particular implementation advantages are gained in the A-D case because no random noise source is required. Results are presented which show also that, in comparison to conventional quantizer dithering, the scheme has excellent dynamic range properties.