Time-skew error correction in two-channel time-interleaved ADCs based on a two-rate approach and polynomial impulse responses

Even though time-interleaved analog-to-digital converters (ADCs) help to achieve higher bandwidth with simpler individual ADCs, gain, offset, and time-skew mismatch between the channels degrade the achievable resolution. Of particular interest is the time-skew error between channels which results in nonuniform samples and thereby introducing distortion tones at the output of the time-interleaved ADC. Time-varying digital reconstructors can be used to correct the time-skew errors between the channels in a time-interleaved ADC. However, the complexity of such reconstructors increases as their bandwidth approaches the Nyquist band. In addition to this, the reconstructor needs to be redesigned online every time the time-skew error varies. Design methods that result in minimum reconstructor order require expensive online redesign while those methods that simplify online redesign result in higher reconstructor complexity. This paper proposes a technique that can be used to simplify the online redesign and achieve a low complexity reconstructor at the same time.