Adaptive calibration method for timing mismatch error in time-interleaved ADC system

Timing-mismatch error is the most important error and has great influence in the mismatch errors of time-interleaved parallel acquisition systems, which can greatly degrade the dynamic range of time-interleaved analog-to-digital converters (TIADCs). In this paper, a novel digital calibration method for the inter-channel timing-mismatch error is proposed, which is based on Farrow structure fractional delay filter combined with adaptive estimation technique. For the purpose of online correction, the timing mismatch errors are obtained adaptively. The mismatch errors are corrected with the fractional delay filter developed in the form of Farrow structure. The proposed method could calibrate the band-limited signals in the first Nyquist zone, and could be used in the TIADC with any number of channels. The simulation experiment results show that the proposed method can estimate the timing-mismatch error accurately, effectively restrain the spurious spurs and has good calibration effect. The effectiveness of the proposed method was verified in an actual time-interleaved acquisition system.