Analysis and Design of Quadrature Oscillators

Modern RF receivers and transmitters require quadrature oscillators with accurate quadrature and low phase-noise. Existing literature is dedicated mainly to single oscillators, and is strongly biased towards LC oscillators. This book is devoted to quadrature oscillatorsand presents adetailed comparative study ofLC and RCosc- lators, both at architectural and at circuit levels. It is shown that in cross-coupled RC oscillators both the quadrature error and phase-noise are reduced, whereas in LC - cillators the coupling decreases the quadrature error, but increases the phase-noise. Thus, quadrature RC oscillators can be a practical alternative to LC oscillators, - pecially when area and cost are to be minimized. The main topics of the book are: cross-coupled LC quasi-sinusoidal oscillators, cross-coupled RC relaxation oscillators, a quadrature RC oscillator-mixer, and t- integrator oscillators. The effect of mismatches on the phase-error and the pha- noise are thoroughly investigated. The book includes many experimental results, obtained from different integrated circuit prototypes, in the GHz range. A structured design approach is followed: a technology independent study, with ideal blocks, is performed initially, and then the circuit level design is addressed. This book can be used in advanced courses on RF circuit design. In addition to post-graduate students and lecturers, this book will be of interest to design engineers and researchers in this area.

The following features of Analysis and Design of Quadrature Oscillators make it different from the existing literature on electronic oscillators:

• focus on quadrature oscillators with accurate quadrature and low phase-noise, required by modern communication systems;
• a detailed comparative study of quadrature LC and RC oscillators, including cross-coupled LC quasi-sinusoidal oscillators, cross-coupled RC relaxation oscillators, a quadrature RC oscillator-mixer, and two-integrator oscillators;
• a thorough investigation of the effect of mismatches on the phase-error and the phase-noise;
• the conclusion that quadrature RC oscillators can be a practical alternative to LC oscillators when area and cost should be minimized (in cross-coupled RC oscillators both the quadrature-error and phase-noise are reduced, whereas in LC oscillators the coupling increases the phase-noise);
• use of a structured design approach, in which a technology independent study, with ideal blocks, is performed initially, and then the circuit level design is addressed;
• inclusion of many experimental results, obtained from different integrated circuit prototypes, in the GHz range.