Model Comparison for 1/f Noise in Oscillators With and Without AM to PM Noise Conversion

A new generalized 1/f Kurokawa noise analysis applicable to both low-and high-oscillators is proposed for 1/f phase modulation (PM) and amplitude modulation (AM) noise. A theoretical correspondence between the new generalized Kurokawa theory and the impulse sensitivity function and the perturbation projection vector (PPV) is also derived in the absence and presence of AM to PM noise conversion. The importance of AM to PM noise conversion effect is investigated next using a modified Van der Pol oscillator with fourth-order nonlinear capacitances and a harmonic short. The same analytic solution for the phase noise is derived for both the new generalized 1/f Kurokawa and the PPV analysis and is found to match the results from the conversion matrix method in two commercial harmonic-balance circuit simulators. The proposed generalized Kurokawa theory is then applied to a bipolar junction transmitter Colpitts oscillator and a CMOS ring oscillator and is verified to yield comparable results to those obtained from the matrix conversion method. Finally, the generalized Kurokawa noise is also found to be able to predict well the experimentally measured ceiling of the voltage noise spectral density at low offset frequencies for a transmission-line pseudomorphic HEMT oscillator.