Title :
Dual-ADC based digital calibration of timing skew for a time-interleaved ADC
Author :
Zhang, Rui ; Yin, Yong-sheng ; Yang, Jun ; Gao, Ming-lun
Author_Institution :
Inst. of VLSI Design, Hefei Univ. of Technol., Hefei, China
Abstract :
The performance of time-interleaved analog-to-digital converters (TIADCs) is seriously restricted by the mismatch of the timing skew between ADC channels. The concept of dual-ADC based calibration is that setting two ADC to sample the same input signal synchronously, and the differences of the two outputs are used in calibration algorithm to estimate and compensate the errors in each ADC. Based on this method, we propose a novel 7-channel TIADC with digital background calibration, which focuses on calibrating the timing skew of each ADC channel. The calibration algorithm is based on the least-mean-square iteration. Simulation of the designed 14-bit 7-channel TIADC with MATLAB shows that, with ± 0.02Ts timing skew, and normalized input frequency fin/fs=0.05, signal to noise and distortion ratio and spurious free dynamic range of the output signal of the TIADC after calibration reach 85.9dBc and 103dBc, and improve 28dBc and 43dBc, respectively, compared to the uncalibrated output signal.
Keywords :
analogue-digital conversion; calibration; iterative methods; least mean squares methods; 14-bit 7-channel TIADC; digital background calibration; dual-ADC based digital calibration algorithm; least mean square iteration; time-interleaved ADC channel; time-interleaved analog-to-digital converter; timing skew; Algorithm design and analysis; Calibration; Channel estimation; Convergence; Error compensation; Least squares approximation; Timing; adaptive calibration; digital calibration; time-interleaved ADC; timing skew;
Conference_Titel :
Image Analysis and Signal Processing (IASP), 2011 International Conference on
Conference_Location :
Hubei
Print_ISBN :
978-1-61284-879-2
DOI :
10.1109/IASP.2011.6108994