Effective dithering of digital delta-sigma modulators, with applications to fractional-N frequency synthesis

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dc.contributor.advisor Kennedy, Michael Peter en
dc.contributor.author Mo, Hongjia
dc.date.accessioned 2017-04-10T11:39:38Z
dc.date.issued 2016
dc.date.submitted 2016
dc.identifier.citation Mo, H. 2016. Effective dithering of digital delta-sigma modulators, with applications to fractional-N frequency synthesis. PhD Thesis, University College Cork. en
dc.identifier.uri http://hdl.handle.net/10468/3868
dc.description.abstract Delta-sigma modulators, both analog and digital, are widely used in a vast range of modern electronic components such as data converters, fractional-N frequency synthesizers, all-digital phase-locked loops and power amplifiers. Digital delta-sigma modulators (DDSMs) have received less attention in the literature in comparison to analog delta-sigma modulators (ADSMs) despite the fact that digital implementations are at least as important as their analog counterparts. This thesis aims to enhance the theoretical understanding of the operation of DDSMs, with a view to developing novel applications for the most popular architectures, namely Error Feedback Modulator (EFM) and Multi stAge noise SHaping (MASH) DDSMs. DDSMs are finite state machines; their spectra are characterized by strong periodic tones (so-called spurs) when they cycle repeatedly in time through a small number of states. This can happen for a range of constant and periodic inputs. Over the past decade, much research has been carried out to find ways to reduce the magnitudes of the spurs produced by DDSMs. Dither generators based on linear feedback shift registers (LFSRs) are widely used to break up periodic cycles in DDSMs. Unfortunately, pseudorandom LFSRs are themselves periodic and therefore may have limited effectiveness. This first part of this thesis presents a rigorous mathematical analysis of DDSMs with LFSR-based dither, and a design methodology to achieve effective dithering. The second part of the thesis presents some practical applications arising from our theoretical work. A nested fractional-N frequency synthesizer which uses a bus-splitting DDSM to allow higher clock frequencies is developed. A MASH DDSM employing higher-order dither noise shaping to eliminate spurious tones is investigated. A mechanism for nonlinear distortion in fractional-N frequency synthesizers arising from the modulo nonlinearity of the DDSM is proposed. en
dc.description.sponsorship Science Foundation Ireland (SFI Grant 13/IA/1979) & (SFI Grant 13/RC/2077); Enterprise Ireland (Grant CC-2009-05) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2016, Hongjia Mo. en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Random number generation en
dc.subject Delta-sigma modulation en
dc.subject Noise shaping en
dc.subject DDSM en
dc.subject PLL en
dc.subject Frequency synthesizer en
dc.subject Dither en
dc.title Effective dithering of digital delta-sigma modulators, with applications to fractional-N frequency synthesis en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PHD (Engineering) en
dc.internal.availability Full text not available en
dc.check.info Restricted to everyone for five years en
dc.check.date 2022-04-09T11:39:38Z
dc.description.version Accepted Version
dc.contributor.funder Science Foundation Ireland en
dc.contributor.funder Enterprise Ireland en
dc.description.status Not peer reviewed en
dc.internal.school Electrical and Electronic Engineering en
dc.check.reason This thesis is due for publication or the author is actively seeking to publish this material en
dc.check.opt-out Yes en
dc.thesis.opt-out true
dc.check.entireThesis Entire Thesis Restricted
dc.check.embargoformat Hard bound copy in Library only en
dc.internal.conferring Summer 2017 en


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© 2016, Hongjia Mo. Except where otherwise noted, this item's license is described as © 2016, Hongjia Mo.
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