Tunable Mismatch Shaping for Quadrature Bandpass Delta-Sigma Data Converters

This paper presents an architecture for quadrature bandpass mismatch shaping that allows the center frequency of the mismatch suppression band to be tunable over the entire Nyquist range. The approach is based on the previously reported complex-valued tree-based mismatch shaper, and extends this to allow tunable operation. The proposed design has been implemented using VHDL and synthesized to logic gates. The hardware complexity and mismatch shaping performance of the proposed architecture are compared to that of a reference architecture, which uses separate tunable mismatch shapers for each complex component path. Simulation results show consistent mismatch shaping performance across the entire tuning range.