A New Interpretation of the Time-Interleaved ADC Mismatch Problem: A Tracking-Based Hybrid Calibration Approach

Time-interleaved analog-to-digital converters (TI-ADCs) can achieve high sampling rates by interleaving multiple sub-ADCs in parallel. Mismatch errors between the sub-ADCs, however, can significantly degrade the signal quality, which is a main performance bottleneck in TI-ADCs. In this letter, we present a hybrid calibration approach by interpreting the mismatch problem as a tracking problem, and use the extended Kalman filter for online estimation of the mismatch errors. After estimation, the input signal is reconstructed using a truncated fractional delay filter and a high-pass filter. Simulations demonstrate that our algorithm substantially outperforms the existing hybrid calibration method in both mismatch estimation and compensation.