Observations and Analysis of Wandering Spurs in MASH-Based Fractional-N Frequency Synthesizers
Abstract
Fractional-N frequency synthesizers can exhibit a phenomenon known as wandering spurs. This brief traces the root cause of the phenomenon to the divider controller. Predictions of the repeat period and the wander rate in the case of a multi-stage noise shaping delta-sigma modulator (MASH DDSM)-based divider controller are given. Simulations, based on CppSim simulations of a type-II CP-PLL with a third-order digital delta-sigma based divider controller, confirm the theoretical predictions.
Publication Title
IEEE Transactions on Circuits and Systems II: Express Briefs
Recommended Citation
Mai, D., Mo, H., & Kennedy, M. (2018). Observations and Analysis of Wandering Spurs in MASH-Based Fractional-N Frequency Synthesizers. IEEE Transactions on Circuits and Systems II: Express Briefs, 65 (5), 662-666. https://doi.org/10.1109/TCSII.2018.2821636
