his paper proposes a computationaly-efficient procedure dedicated to time-domain phase noise (PN) modeling of a phase-locked loop (PLL)-based frequency synthesizer in a radio-frequency (RF) context. The structure proposed is able to describe any kind of PN including thermal and flicker noise regions using time-domain equations. The design process of the phase noise modeling process is detailed. An expression of the estimated mean square error (MSE) of the frequency response of the PN generating system is proposed and compared to a previously proposed PN generating system. The spectral behaviour of the simulated frequency synthesizer is compared to practical PN measurements obtained with a spectral analyzer.