EURASIP Journal on Advances in Signal Processing
Volume 2008 (2008), Article ID 513706, 11 pages
doi:10.1155/2008/513706
Research Article

Adaptive Reference Levels in a Level-Crossing Analog-to-Digital Converter

Karen M. Guan,1 Suleyman S. Kozat,2 and Andrew C. Singer1

1Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 60801, USA
2Department of Computer Engineering, College of Engineering, Koc University, 34450 Istanbul, Turkey

Received 24 October 2007; Revised 30 March 2008; Accepted 30 June 2008

Academic Editor: Sergios Theodoridis

Copyright © 2008 Karen M. Guan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Level-crossing analog-to-digital converters (LC ADCs) have been considered in the literature and have been shown to efficiently sample certain classes of signals. One important aspect of their implementation is the placement of reference levels in the converter. The levels need to be appropriately located within the input dynamic range, in order to obtain samples efficiently. In this paper, we study optimization of the performance of such an LC ADC by providing several sequential algorithms that adaptively update the ADC reference levels. The accompanying performance analysis and simulation results show that as the signal length grows, the performance of the sequential algorithms asymptotically approaches that of the best choice that could only have been chosen in hindsight within a family of possible schemes.