Analysis and reduction of the oscillator phase noise from the variance of the phase deviations, determined with harmonic balance

The stochastic time domain characterization of the noisy oscillator allows an accurate prediction of the variance of the phase deviation. In this work, it is demonstrated that the magnitudes that determine this variance can be obtained from a harmonic-balance analysis with the carrier modulation approach. Once the variance of the phase deviation is known, a general technique is derived to obtain the complete phase-noise spectrum in the presence of white and colored noise sources. Finally a design procedure is presented to minimize the phase noise around the carrier or away from the carrier. The techniques have been applied to a MESFET oscillator at 5 GHz.