Wandering spurs in MASH 1-1 delta-sigma modulators
Kennedy, Michael Peter
Institute of Electrical and Electronics Engineers (IEEE)
Wandering spurs are a little-studied phenomenon seen in MASH and SQ-digital delta-sigma modulators. They take the form of frequency-modulated spurs which periodically appear in-band. Since modulators are often employed as divide ratio controllers in fractional-N phase lock loops, these spurs can feed into the output phase noise spectrum. In this paper, we explain the mechanism which creates the wandering spurs and offer a prediction for the behavior of these spurs in the MASH 1-1 modulator. Simulation results are presented which confirm our theoretical predictions.
Multi-stage noise shaping , Delta-sigma modulation , Phase locked loops , Frequency modulation , Phase modulation , Phase noise , Wandering spur , PLL , MASH , Experimental , Modulator , Delta-sigma , Spectrum , Spur , Phase lock loop , Frequency modulation.
Donnelly, Y. and Kennedy, M.P. (2019) 'Wandering spurs in MASH 1-1 delta-sigma modulators', IEEE Transactions on Circuits and Systems I: Regular Papers, pp. 1-14. doi:10.1109/TCSI.2019.2893435
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