Mitigation of 'Horn Spurs' in a MASH-Based Fractional-N CP-PLL
Abstract
A Fractional-N Charge Pump (CP) PLL with a Multi-stAge noise SHaping (MASH) 1-1-1 divider controller has been reported to exhibit pairs of spurious tones called 'horn spurs'. The phenomenon has been confirmed in measurements on a commercial wideband synthesizer. This brief presents an analysis of the phenomenon and techniques to mitigate it. MATLAB simulation results are presented for a type-II CP-PLL with a third order MASH Digital \Delta \Sigma Modulator (DDSM) to validate the techniques that are shown. Measurement results are also presented.
Publication Title
IEEE Transactions on Circuits and Systems II: Express Briefs
Recommended Citation
Mazzaro, V., & Kennedy, M. (2020). Mitigation of 'Horn Spurs' in a MASH-Based Fractional-N CP-PLL. IEEE Transactions on Circuits and Systems II: Express Briefs, 67 (5), 821-825. https://doi.org/10.1109/TCSII.2020.2984359
