Modeling and Phase Noise Improvement in Ring Oscillator

Please enable javascript in your browser.

Sadeghi Ghogheri, Hesam | 2014

485 Viewed

Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 46746 (05)
University: Sharif University of Technology
Department: Electrical Engineering
Advisor(s): Sharif Bakhtiar, Mehrdad
Abstract:
We present a model for noise in Ring Oscillator in order to improve their phase noise. Each Ring Oscillator consists of some nonlinear blocks. We study effect of these blocks on phase noise. In this study, noise behavior of each block is analyzed and a design guide for improvement of noise characteristic is presented.
It is essential for phase noise improvement to obtain insight about operation mechanism of oscillator. A comprehensive model is presented to get this insight. In this model, we show how a noise current produces phase noise also, a formula for phase noise is derived.
In second step, phase noise of Ring oscillator is improved by using the model. Active inductor is used in oscillator structure also a novel model is presented for nonlinear behavior of active inductor.
Finally, a new three stage Ring oscillator is designed in 0.18 CMOS technology. Simulations results prove that FOM (@ 1 MHz) of new Ring oscillator is improved about 5.5dB in comparison to conventional Ring Oscillator
Keywords:
Phase Noise ; Modeling ; Ring Oscillator

No TOC