Methods for the transfer function design of multiple narrow-band bandpass sigma-delta modulators

摘要

This paper presents the design analysis of novel tunable narrow-band bandpass sigme-delta modulators, which can achieve concurrent multiple noise-shaping for multi-tone input signals. Four different design methodologies based on the noise transfer functions of comb filters, slink filters, multi-notch filters and fractional delay comb filters are applied for the design of these multiple-band sigma-delta modulators. The latter approach utilises conventional comb filters in conjunction with FIR, or allpass IIR fractional delay filters, to deliver the desire nulls for the quantisation noise transfer function.