On phase noise in quadrature cross-coupled oscillators

Author

Oliveira, Luís Bica ; Allam, A. ; Filanovsky, I.M. ; Fernandes, Jorge R.

Author_Institution

I.S.Tecnico/TNESC-ID Lisboa, Portugal

fYear

2005

fDate

23-26 May 2005

Firstpage

2635

Abstract

A cross-coupled relaxation oscillator has two outputs of the same frequency, which are in quadrature. In this paper a comparative study of the phase noise in a cross-coupled relaxation oscillator is given. We present a high level (system) study of the oscillator and analyse the oscillator stability. The derivation proves analytically that cross-coupling reduces the influence of a perturbation (noise) on the oscillator output. Both high-level and circuit simulations at 5GHz are presented to confirm the theoretical results. Close to 10dB improvement in phase noise performance due to coupling was found, and the phase noise performance compared with that of a coupled LC oscillator was achieved.

Keywords

circuit simulation; circuit stability; delays; phase noise; relaxation oscillators; circuit simulations; oscillator stability; phase noise; quadrature cross-coupled oscillators; relaxation oscillator; Circuit simulation; Circuit stability; Coupling circuits; Delay; Frequency; Inductors; Mathematical model; Oscillators; Phase noise; Stability analysis; Relaxation oscillator; cross-coupled oscillator; delay; phase noise;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2005. ISCAS 2005. IEEE International Symposium on

Print_ISBN

0-7803-8834-8

Type

conf

DOI

10.1109/ISCAS.2005.1465167

Filename

1465167