UCLA Extension

Delta-Sigma Modulation for Phase-Locked Loops and Data Converters

Digital techniques are now widely used to improve traditional analog circuits. These new systems achieve exceptional performance and make possible advanced architectures.

Complete Details

Delta-sigma modulation is a popular digital technique to reduce analog complexity and accuracy requirements. It uses oversampling and noise shaping to mitigate the effects of analog imperfections and to boost performance. The designs emphasize digital networks with near-exact accuracy.

The design of the delta-sigma modulator varies with the application and its requirements. Simple structures can be readily used in fractional-N phase-locked loops. Error feedback networks are ideal for D/A converters but not for A/D converters. Moreover, bandpass designs introduce new opportunities and challenges.

This course provides detailed information about over-sampled delta-sigma modulation structures. The detailed design of a fractional-N phase-locked loop and the impact on its phase noise profile is examined. The design of several data converters, both low-pass and band-pass approaches, is also covered. Along the way, key circuit requirements are indicated. Emphasis is on the mathematical, as well as the practical, aspects of design.

Upon completing this course, you should:

  • Understand the operation of various delta-sigma modulator structures
  • Synthesize the underlying transfer functions
  • Shape the phase noise profile of fractional-N phase-locked loops
  • Simulate the performance of different oversampled data converters
  • Investigate techniques to boost performance

Course Materials

Lecture notes are distributed on the first day of the course. A disk with several MATLAB models of the design examples is also provided. These materials are for participants only and are not otherwise available for sale or unauthorized distribution.

Coordinator and Lecturer

John B. Groe, MS, Principal Consultant, Innovate Radio, San Diego, California. Mr. Groe has been investigating and developing wireless systems for over 25 years. During this time, he has designed several radio transceivers for a wide range of applications, such as cellular, medical, smart grid, and military systems. He also has extensive experience with advanced radio architectures and key circuits, including direct conversion approaches, RF sampling, fractional-N phase-locked loops, over-sampled data converters, wide bandwidth envelope tracking, and polar modulation.

Mr. Groe’s research focuses on digital techniques to improve radio performance. He combines in-depth system and circuit knowledge to develop advanced solutions. His research has led to 57 patents and several other applications.

Mr. Groe is the author of a number of journal papers, is a peer reviewer, and is a Senior Member of IEEE. He coauthored CDMA Mobile Radio Design and is a contributor to Circuits and Systems for Future Generations of Wireless Communications. He is a part-time professor at UCSD and a guest lecturer at UCLA.

Course Program

Introduction to Over-Sampled Delta-Sigma Modulators
Oversampling and quantization noise, noise shaping, noise and signal transfer functions, transfer function synthesis, pole-zero mapping, low-pass structures, and band-pass structures.

Fractional-N Phase-Locked Loop
Operation; simple modulator; higher order structures; stability; re-sync benefit; phase noise profile; shaping phase noise; periodic sequences, nonlinearity, and spurs; dither; cancelling phase noise; and design examples.

Error Feedback D/A Converters
Error feedback concept, low-pass transfer function, shaping noise spectrum, band-pass transfer function, extended structure, stability, and design examples.

A/D Converters
Basic overview, cascade structure, MASH structure, loop topologies, and design examples.

Other Topics
Multi-bit quantizers, bandwidth limitations, circuit issues, calibration, dynamic element matching, sample rate conversion, digital filters, and jitter.

MATLAB Toolbox
Review of some useful functions.

For more information contact the Short Course Program Office:
shortcourses@uclaextension.edu | (310) 825-3344 | fax (310) 206-2815

image_print