Calibration of timing offsets in a four-channel time-interleaved ADCs

This paper describes a digital calibration method for reducing the distortion created by timing mismatch in a four-channel time-interleaved analog-to-digital converter (TIADC). It bases on a coordinate rotation digital computer (CORDIC) algorithm for estimating the timing error and a multistage differentiator-multiplier cascade structure for timing error correction. Frequency of the testing signal using for estimation almost ranges from zero to Nyquist frequency of the system. For correction method, the differentiators are implemented with fixed filter coefficients and only several multipliers need to be adapted during operation such that implementation costs are reduced. Moreover, numerical simulations show a rather high performance for both estimation and correction.