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Mathematical Problems in Engineering
Volume 2015, Article ID 689869, 9 pages
http://dx.doi.org/10.1155/2015/689869
Research Article

A Statistic-Based Calibration Method for TIADC System

1School of Automation Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
2School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798

Received 7 July 2014; Accepted 22 December 2014

Academic Editor: Marcelo M. Cavalcanti

Copyright © 2015 Kuojun Yang 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

Time-interleaved technique is widely used to increase the sampling rate of analog-to-digital converter (ADC). However, the channel mismatches degrade the performance of time-interleaved ADC (TIADC). Therefore, a statistic-based calibration method for TIADC is proposed in this paper. The average value of sampling points is utilized to calculate offset error, and the summation of sampling points is used to calculate gain error. After offset and gain error are obtained, they are calibrated by offset and gain adjustment elements in ADC. Timing skew is calibrated by an iterative method. The product of sampling points of two adjacent subchannels is used as a metric for calibration. The proposed method is employed to calibrate mismatches in a four-channel 5 GS/s TIADC system. Simulation results show that the proposed method can estimate mismatches accurately in a wide frequency range. It is also proved that an accurate estimation can be obtained even if the signal noise ratio (SNR) of input signal is 20 dB. Furthermore, the results obtained from a real four-channel 5 GS/s TIADC system demonstrate the effectiveness of the proposed method. We can see that the spectra spurs due to mismatches have been effectively eliminated after calibration.