文档介绍：326 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 35, NO. 3, MARCH 2000
Oscillator Phase Noise: A Tutorial
Thomas H. Lee, Member, IEEE, and Ali Hajimiri, Member, IEEE
Abstract—Linear time-invariant (LTI) phase noise theories
provide important qualitative design insights but are limited in
their quantitative predictive power. Part of the difficulty is that
device noise undergoes multiple frequency translations to e
oscillator phase noise. A quantitative understanding of this process
requires abandoning the principle of time invariance assumed in
most older theories of phase noise. Fortunately, the noise-to-phase Fig. 1. “Perfectly efficient” RLC oscillator.
transfer function of oscillators is still linear, despite the existence
of the nonlinearities necessary for amplitude stabilization. In addi- we discover that periodic time variation leads to frequency
tion to providing a quantitative reconciliation between theory and
measurement, the time-varying phase-noise model presented in translation of device noise to produce the phase-noise spectra
this tutorial identifies the importance of symmetry in suppressing exhibited by real oscillators. In particular, the upconversion
the upconversion of 1 noise into close-in phase noise, and of 1 noise into close-in phase noise is seen to depend on
provides an explicit appreciation of cyclostationary effects and symmetry properties that are potentially controllable by the
AM–PM conversion. These insights allow a reinterpretation of designer. Additionally, the same treatment easily subsumes
why the Colpitts oscillator exhibits good performance, and suggest
new oscillator topologies. Tuned LC and ring oscillator circuit the cyclostationarity of noise generators, and helps explain
examples are presented to reinforce the theoretical considerations why class-C operation of active elements within an oscillator
developed. Simulation issues and the modation of amplitude may be beneficial. Illustrative circuit examples