Sub-Harmonic and Rational Synchronization for Phase-Noise Improvement

In an injected oscillator, synchronization bands (or Arnold tongues) are theoretically obtained at rational ratios between the frequencies of the generator and the self-oscillation. Here an in-depth analysis of this phenomenon is carried out. A simple and accurate technique is presented for the harmonic-balance prediction of the subharmonic and rational synchronization bands. Two designs of a synchronized MESFET-based oscillator at the respective ratios ¿ and a ¿ are presented, with the simulation and measurement of the steady-state regime. A good improvement of the free-running oscillator phase noise has been achieved.