Another moving Spur Phenomenon observed in a MASH-based Fractional-N PLL

Recently, other authors have experienced and analysed what has been called wandering spurs. This paper presents observations of what seems to be a similar phenomenon obtained under different simulation conditions. Results are given based on Matlab/Simulink simulations of a type-II CP-PLL with a third order MASH DDSM. Analysis of the repeat period and the rate of the spurs are presented.