A review of low noise oscillator. Theory and design

A large number of papers have been published on low noise oscillators, however they are usually very specific to the particular application. This paper describes a set of design rules which are general and can be used to produce oscillators with very low noise performance where both additive (thermal noise) and flicker noise are considered. Linear theories are described which accurately describe the noise performance of resonator type oscillators. The limits set by varactor diodes on the noise performance in tuneable oscillators are described and the noise degradation caused by open loop phase error is shown. Several design examples are included and these show close correlation with the theory.