Event-driven Simulation and modeling of phase noise of an RF oscillator

A novel simulation technique that uses an event-driven VHDL simulator to model phase noise behavior of an RF oscillator for wireless applications is proposed and demonstrated. The technique is well suited to investigate complex interactions in large system-on-chip systems, where traditional RF and analog simulation tools do not work effectively. The oscillator phase noise characteristic comprising of flat electronic noise, as well as, upconverted thermal and 1/f noise regions are described using timedomain equations and simulated as either accumulative or nonaccumulative random perturbations of the fundamental oscillator period. The VHDL simulation environment was selected for its high simulation speed, the direct correlation between the simulated and built circuits and its ability to model mixed-signal systems of high complexity. The presented simulation technique has been successfully applied and validated in a Bluetooth transceiver integrated circuit fabricated in a digital 130-nm process.