Blind adaptive calibration of timing error for two- channel time-interleaved ADCs

The time-interleaved analog-to-digital converter is an efficient approach to systems requiring very high sampling rate with medium to high resolution. However, the inter-channel mismatch and process variations introduce additional errors as compared to single-channel ADC, which results in degradation of the ADC performance. The mismatches include gain, offset and timing, among which the timing errors are particularly important since it is often input dependant and time-variant. In this paper, a blind adaptive method is proposed to calibrate the timing error in a 2-channel TIADC system. It is based on a derived goal function with Least Means Square algorithm which estimates the timing error adaptively. A Farrow structure and mirror-based modulation method are employed to calibrate the timing mismatch. The proposed method is of low complexity and is able to track slow drift of the timing mismatch.