Efficient signal reconstruction scheme for time-interleaved ADCs

Time-interleaved analog-to-digital converters (ADCs) exhibit offset, gain, and time-skew errors due to channel mismatches. The time skews give rise to a nonuniformly sampled signal instead of the desired uniformly sampled signal. This introduces the need for a digital signal reconstructor that takes the “nonuniform samples” and generates the “uniform samples”. In the general case, the time skews are frequency dependent, in which case a generalization of nonuniform sampling applies. When the bandwidth of a digital reconstructor approaches the whole Nyquist band, the computational complexity may become prohibitive. This paper introduces a new scheme with reduced complexity. The idea stems from recent multirate-based efficient realizations of linear and time-invariant systems. However, a time-interleaved ADC (without correction) is a time-varying system which means that these multirate-based techniques cannot be used straightforwardly but need to be appropriately analyzed and extended for this context.