An Adaptive Blind Frequency Response Mismatches Calibration Technique for 4-Channel Time-Interleaved ADCs

This paper proposes a novel digital blind calibration technique to calibrate the frequency response mismatches (FRMs) in 4-channel time-interleaved analog-to-digital converter (TI-ADC). Based on the frequency-shifted basis functions generated from the measured TI-ADC output, the FRMs could be constructed blindly and then subtracted from the TI-ADC output adaptively. The advantage of the proposed technique is that it only needs to know the measured output signal without needing any additional information; and it is applicable to 4-channel TI-ADCs with no limitations to the sub-ADC sampling rate and input signal type. Specifically, the basis function generator only employs a Hilbert filter and does not need extra FIR filters. In addition, the numerical simulations have been presented to demonstrate the effectiveness and superiority of the proposed technique, which shows that the proposed technique can improve the SNR by 20 dB and the SFDR by 25 dB.