Mixing Oscillators for Phase Noise Reduction

TL;DR

This paper introduces a circuit that combines multiple oscillators to reduce phase noise by averaging their phase variations, improving signal stability.

Contribution

It presents a novel circuit design for phase noise reduction by averaging multiple oscillators' phase noise processes, including theoretical analysis for Wiener-modeled noise.

Findings

Lower phase noise variance achieved

Effective averaging of multiple oscillators

Theoretical analysis confirms noise reduction benefits

Abstract

The output of oscillators is usually not stable over time. In particular, phase variations---or \emph{phase noise}---corrupts the oscillations. In this letter, we describe a circuit that designed to average the phase noise processes and frequency offsets in frequency-matched oscillators. The basic circuit uses the independence of 2 phase noise processes to provide a cleaner oscillating output with lower phase noise variance. We describe extensions of the circuit designed to average out more than 2 oscillators, as well as a single one through delay elements. In all the examples covered, we provide a theoretical analysis of the resulting phase noise process when the input phase noise processes follow a Wiener model.