A Signal Processing View on Time-Interleaved ADCS

The idea of time-interleaved ADCs (TI-ADCs) is old, but it took more than 25 years until the requirements on converters and the possibility of advanced digital post correction made this architecture attractive. We investigate timeinterleaved ADCs with a focus on the involved signal processing. By establishing a discrete-time model of a TI-ADC, we explicitly show that a TI-ADC with mismatches is a time-varying system producing spurious images. This view will help to understand the principles of digital calibration of linear mismatches in TI-ADCs. Currently, time offset mismatches are investigated most extensively. Therefore, we will primarily discuss digital calibration of time offset mismatches, but will generalize the results to frequency response mismatches whenever possible.