A Fully Digital Background Calibration of Timing Skew in Undersampling TI-ADC

International audience<p>Abstract—This paper proposes a fully digital calibration oftiming mismatch for undersampling Time Interleaved Analog-to-Digital Converter (TI-ADC) employed in Software Defined Radio (SDR) receivers. The proposed calibration scheme employs an ideal differentiator filter, a Hilbert transform filter and a scaling factor to compute the derivative of the input in any Nyquist Band (NB). The efficiency of the proposed technique is shown using a four-channel undersampling 60 dB SNR TI-ADC clocked at 2.7 GHz. Monte Carlo simulations show SNDR and SFDR improvements ofrespectively,18 dB and 21 dB over the first three NBs.