Blind Calibration of Mismatch Errors in Multichannel Asynchronous Time-Interleaved ADCs

Asynchronous time interleaved (ATI) analog-to-digital converter (ADC) architectures employ pre-processing, low-pass filtering, and ADCs to simultaneously enhance the sample rate and bandwidth of acquisition systems. However, non-idealities in ATI architecture can degrade performance. This article proposes a blind calibration approach to compensate for mismatch errors in ATI systems. The advantage of this approach is that it does not interfere with the normal operation of the ADC and signal acquisition, allowing the calibration process to be performed concurrently. The approach is based entirely on the ATI output sequence, without requiring additional information or reference channels, which facilitates blind operations. It autonomously detects the sub-band in which the signal resides, allowing calibration of both single-tone and multitone signals without prior knowledge. Once the sub-band is identified, blind calibration is applied to the sampling sequence. Finally, the performance of the proposed approach was evaluated on a four-channel hardware prototype. Satisfactory results are obtained and the feasibility of the proposed approach are demonstrated.