Compensation of track and hold frequency response mismatches in interleaved analog to digital converters for high-speed communications

• Published in: 2006 IEEE International Symposium on Circuits and Systems (ISCAS) pp. 4 pp. - 1634
• Main Authors: Luna, G.C., Crivelli, D.E., Hueda, M.R., Agazzi, O.E.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2006
• Subjects: Analog-digital conversion; Decision feedback equalizers; Digital signal processing; Frequency conversion; Frequency response; Maximum likelihood estimation; MIMO; Optical amplifiers; Optical receivers; Signal to noise ratio
• ISBN: 0780393899; 9780780393899
• ISSN: 0271-4302; 2158-1525
• DOI: 10.1109/ISCAS.2006.1692914

In this paper, we investigate the effect of mismatches in the frequency responses of the track-and-hold (T&H) amplifiers of an interleaved array of analog-to-digital converters (ADC) used as the front-end of a high-speed communications receiver. Furthermore, we introduce digital signal processing (DSP) techniques to compensate the performance loss caused by these mismatches. These techniques take advantage of the specific application of the ADC as a front-end of a digital communication receiver, assumed to be based on a parallel processing implementation of a decision-feedback equalizer (DFE) (Kasturia and Winters, 1991; Parhi, 1999). With a relatively simple modification, the DFE can be transformed into a multiple-input, multiple-output (MIMO) equalizer. The latter effectively compensates the effect of the T&H frequency response mismatch. The performance measure used in this paper is the signal to noise ratio (SNR) at the slicer. An SNR loss of 2.5 dB or more could result from the T/H mismatch. Most of this loss is compensated by the MIMO equalizer. Our conclusions can be easily extended to receiver architectures other than the DFE, for example maximum-likelihood sequence estimation (MLSE) (Agazzi, 2005). As an example of the effectiveness of the techniques introduced here, we present an optical receiver with electronic dispersion compensation (EDC) for the emergent IEEE 802.3aq standard for 10 Gb/s Ethernet over multimode fibers