System Optimization Design of High-Order Two-Channel Time-Interleaved ∑Δ Modulator Based on Digital Block Filter

Time-interleaving is an efficient approach to increase the sampling rate of ∑Δ modulators, but time-interleaved(TI) ∑Δ modulators are sensitive to channel mismatch. Recently, a solution for this problem has been proposed with a zero of z=-1 and its corresponding pole in the noise transfer function. Based on the proposed second-order two-channel TI modulator, an approach of system optimization design is presented for high-order two-channel TI modulators. The system stability and optimization of zeros/poles are considered. As an example, a system of high-order two-channel TI ∑Δ modulator is designed with bandwidth of 4 MHz, which is suitable for application of digital video broadcasting-terrestrial (DVBT). Simulation results show that the proposed ∑Δ modulator has a large input signal range and is insensitive to channel mismatch.