Computational algorithms for fractional-N PLL noise simulation in the phase domain

This paper presents an approach of fractional-N PLL noise simulation by phase-domain macromodeling. The periodic noise simulation of PLL blocks defines physical noise sources of the micromodel. The quantization noise obtained by the simulation of sigma-delta modulator is considered as additional micromodel noise source. The independence of the quantization noise on the number of simulation steps is provided due to the developed averaging algorithm. Frequency translation effect is taken into account in the micromodel noise analysis.