PPV-Based Modeling and Event-Driven Simulation of Injection-Locked Oscillators in System Verilog

Injection-locked oscillators (ILO) have widespread use in wireline and wireless systems as fast-locking clock generators, phase noise filters, and frequency multipliers/dividers, but their modeling and simulation typically resort to SPICE due to their nonlinear,time-varying characteristics. This paper presents a way to simulate ILOs in an event-driven logic simulator such as SystemVerilog, based on a perturbation projection vector (PPV) model. By expressing the continuous-time signals in analytical forms of which coefficients are updated as events, the nonlinear phase response of the ILO can be simulated in an algebraic fashion without numerical integration. The simulation methodology is demonstrated with the modeling examples of a phase-locked loop and a burst-mode clock recovery loop, each employing a injected-locked frequency divider and oscillator, respectively.