Local oscillators are key buildings in radio communication system. They are considered as intensively analog blocks and then more sensitive to internal noise than digital blocks. This noise is up-converted to phase noise around the carrier frequency at the output of the oscillator. High performance of lo in terms of low phase noise is paid by high surface circuit or by high power consumption. One solution, proposed in the literature, is the all digital phase locked loops ADPLL. Within, digital blocks replace the analog blocks, such as the phase comparator and the loop filter. In this thesis, down to top behavior model of ADPLL is developed using VHDL-AMS. This model includes oscillator phase noise and TDC quantification noise. The modeling ...