A robust 3rd order low-distortion multi-bit sigma-delta modulator with reduced number of op-amps for WCDMA. - Kin-Sang Chio; Seng-Pan U.; Rui Paulo Martins (ISCAS (4), 2005)

A dual-mode low-distortion sigma-delta modulator with relaxing comparator accuracy. - Kin-Sang Chio; Seng-Pan U.; Rui Paulo Martins (ISCAS, 2006)