A stable high-order delta-sigma modulator with an FIR spectrum distributor

A stable high-order delta-sigma modulator topology is presented. The topology can be completely stabilized for arbitrary order by a finite impulse response (FIR) spectrum distribution technique. The stability of the modulator is examined by means of the root locus method. The topology inherently has less sensitivity to component mismatch, and can be realized without any hardware penalty compared to noise-shaping integrators of the same order. The modulator realizes 16-b resolution at 20-kHz bandwidth when a filter order of four and an oversampling ratio of 64 are employed.<
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