Nonlinear analysis of pulsed injection-locked oscillators

Previous works have demonstrated the advantages of pulsed-waveform injection-locked oscillators for the generation of ultrawideband signals. Among these advantages are the quick oscillation start-up and the low phase noise. Here an in-depth nonlinear analysis of these circuits is presented, clarifying the locking mechanism and enabling the determination of the synchronization band versus the pulse frequency. A Poincaré map technique is applied to detect the qualitative stability change that delimits the locked-operation range. The response to small noise perturbations is analyzed and related to the phase noise spectrum. The analysis has been applied to an oscillator at 5 GHz obtaining very good agreement with the measurement results.