Simulation and Experimental Investigation of a Nonlinear Mechanism for Spur Generation in a Fractional-N Frequency Synthesizer

The performance of fractional-N frequency synthesizers in wireless communications applications is degraded by the presence of spurious tones. While the Digital Delta-Sigma Modulator (DDSM) can be directly responsible for the production of such tones, a range of deterministic and stochastic technique...

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Bibliographic Details
Main Authors: Sadeghi, V.S, Saeed, S.I, Calnan, S, Kennedy, M.P, Naimi, H.M, Vesterbacka, M
Format: Conference Proceeding
Language:English
Subjects:
A/D and D/A convertors
Mobile radio systems
Signal generators
Online Access:Get full text
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Summary:The performance of fractional-N frequency synthesizers in wireless communications applications is degraded by the presence of spurious tones. While the Digital Delta-Sigma Modulator (DDSM) can be directly responsible for the production of such tones, a range of deterministic and stochastic techniques have been invented to eliminate the principal causes associated with the architecture of the DDSM. A second source of spurs, when the spectrum of the DDSM iteself is spur-free, is (analogue) nonlinearities in the synthesizer. Recent work has predicted that specific nonlinearities will produce tones at well-defined frequencies; this paper presents simulation and experimental verification of the prediction. (6 pages)
DOI:10.1049/ic.2012.0179