Time-varying analysis helps build high-performance oscillators

A stable and precise time reference is crucial to the operation of, among others, communications systems, digital electronic circuits and banking systems. In wireless communication systems, time and frequency references are provided by an oscillator or a voltage-controlled oscillator. However, noise and physical imperfections of the oscillator components cause frequency instabilities that degrade the quality of signal transmission and reception. Furthermore, voltage-controlled oscillators with a wide tuning range typically exhibit greater frequency instability.

“A solution that breaks the tradeoff between phase noise performance and wide tuning range is needed,” says Broussev.

In his dissertation, Broussev presents circuit topologies that cover a wide frequency range and do not significantly affect the frequency stability. The solutions have the potential to be applied in modern multi-standard communication devices.

The time-varying analysis method developed by Broussev sheds light on the physical phenomena in oscillators and thereby helps in the development of high-performance oscillators. The method carries both physical meanings and analysis precision, which are utilized in comparing and analyzing oscillators. The method has been verified through simulations and measurements and has the potential to become an auxiliary tool for oscillator characterization.
 

Public defense of a doctoral dissertation on Monday, 28 May
 

The doctoral dissertation of MSc Svetozar Broussev in the field of telecommunications “High-Performance LC-VCOs and their Analysis using Time-Varying Root-Locus” will be publicly examined at the Faculty of Computing and Electrical Engineering of Tampere University of Technology (TUT) in room TB104 in the Tietotalo building (address: Korkeakoulunkatu 1, Tampere, Finland) on Monday, 28 May 2012 at 12:00.

The opponent will be Professor Stephen I. Long (University of California, Santa Barbara, USA). Professor Nikolay T. Tchamov from TUT’s Department of Communications Engineering will act as Chairman.

Svetozar Broussev (34) comes from Laki, Bulgaria, and works as a researcher at the RFCC Laboratory of the Department of Communications Engineering of TUT.

Further information:
Svetozar Broussev, tel. +358 40 844 8240, svetozar.broussev@tut.fi