Phase Noise Reduction in an Oscillator Using Harmonic Mixing Technique

This thesis presents a new technique of injection of multi-harmonics into an oscillator, study the behavior and response of the oscillator. First general locking equations are derived using the feedback model of an oscillator. Second, using the Laplace domain modeled phase noise analysis giving insight into the phase noise model of an oscillator under multiple harmonics are analytically studied and experimentally validated with good agreement. From the locking process and phase noise analysis we can observe when compared to single tone injection there is a substantial improvement of phase noise under multi-harmonic injection, enhancement in the locking range. We present Injection Locked Frequency Divider (ILFD) circuit under multi-harmonic injection (2nd and 3rd harmonics injected) with simulation, theoretical validation. The proposed circuit is designed using the UMC library by using Op-Amp based feedback current reference circuit. The amplitude dependency of the injection signals on the phase noise is observed as increase in the injection levels decreases the phase noise