A Novel Two-Channel Time-Interleaved Forth-Order Sigma-Delta Modulator Topology

Time-interleaved (TI) sigma-delta modulators are sensitive to channel-mismatches. In this paper, a new type of noise transfer function (NTF) which is a band-pass filter is adopted for the two-channel TI modulators to reduce the folded noise. Employing the concept of block digital filtering and theory of multirate operations, a novel two-channel TI high-order modulator is derived from the prototype of a conventional single-channel modulator. The simulation results show that the proposed modulator is insensitive to channel mismatches.