Linear LMS Compensation for Timing Mismatch in Time-Interleaved ADCs

• Published in: IEEE transactions on circuits and systems. I, Regular papers Vol. 56; no. 11; pp. 2476 - 2486
• Main Authors: Marelli, D., Mahata, K., Minyue Fu
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.11.2009; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Analog-digital conversion; Analog-digital conversion (ADC); Australia; Band spectra; Circuits; Compensation; Computer science; Digital filters; Frequency; least mean squares (LMS) methods; Least squares approximation; Multiplexing; multirate digital filters; Optimization; Performance loss; Reconstruction; sampled-data systems; Sampling; Sampling methods; signal reconstruction; stochastic systems; Testing; Time measurements; Timing
• ISSN: 1549-8328; 1558-0806
• DOI: 10.1109/TCSI.2009.2015730

The time-interleaved architecture permits the implementation of high-frequency analog-to-digital converters (ADCs) by multiplexing the output of several time-shifted low-frequency ADCs. An issue in the design of a time-interleaved ADC is the compensation of timing mismatch, which is the difference between the ideal and real sampling instants. In this paper, we propose a compensation method that, as opposite to existing approaches, does not assume that the input signal is band limited but assumes instead that it has a stationary known power spectrum. The compensation is then designed in a statistically optimal sense. This largely reduces the compensation order required to achieve a given reconstruction accuracy. Also, under the band-limited assumption, the proposed method achieves perfect reconstruction if no constraints are imposed on the order of the compensation. Simulation results show that a rough estimate of the input spectrum can be used without much performance loss, showing that an accurate knowledge of the input spectrum is not necessarily required.