ESSCIRC 2021 - IEEE 47th European Solid State Circuits Conference (ESSCIRC) | 2021
Experimental Verification of Wandering Spur Suppression Technique in a 4.9 GHz Fractional-N Frequency Synthesizer
Abstract
Apart from the well-known nonlinearity-induced fixed spurs, a DDSM divider-based fractional-$N$ frequency synthesizer can manifest spurs with time-varying frequency offsets from the carrier; these are called wandering spurs. This paper presents experimental results for a 4.9 GHz CP-PLL fractional-$N$ PLL featuring a modified MASH-based divider controller that implements wandering spur suppression. The synthesizer achieves a 20 dB reduction in the spectral envelope of the short-term output phase noise spectrum when compared to the standard MASH DDSM divider controller.