Physical model of phase noise in feedback oscillator

Abstract

The paper mainly focuses on the effect on the oscillator phase noise by the loaded quality factor Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> in Classical Leeson Model, derives that the equivalent circuit parameters of resonator and the oscillation circuit parameters have conclusive concern with the loaded quality factor Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> . And the experimental verification is made on the basis of two kinds of oscillator circuits (Pierce oscillator circuit and Butler common-base oscillator circuit) and three kinds of acoustic resonators (120MHz SC-cut crystal resonator, 315 MHz one-port SAW resonator and 10.7 MHz LiTaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> BAW resonator). The further experiment shows the changes of the crystal oscillator phase noise with different drive levels and presents that besides some parameters such as Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> , the crystal resonator amplitude-frequency (AF) characteristics can also affect the oscillator phase noise apparently. And then, the acoustic oscillator phase noise model can be established on the basis of the physics, which contains the resonator equivalent parameters, the oscillator circuit parameters and the affection of the resonator AF characteristics.