The fast time-interleaved ADC channel mismatch calibration method based on equivalent sampling and dynamic reference point

Abstract

This paper designs an efficient channel mismatch calibration method for TIADC (time-interleaved analog-to-digital converter) system, in order to reduce the complexity and inefficiency of the conventional correction methods. Based on the principle of equivalent sampling, the sampling data of a certain number of cycles is overlapped to one cycle high-resolution data, from which all parameters needed to correct channel mismatch, such as average value, amplitude range and phase, can be acquired, so the calibration of the offset mismatch, gain mismatch and time mismatch can be realized at the same time, avoiding the great calculation of FFT or curve fitting. By normalizing the three parameters, these channels can be turned into points in the three dimensional space, the point with smallest distance sum respected to all the other points can be chosen as the reference channel, the calibration time is reduced consequently. Simulation and application results show that the method can measure above-mentioned errors rightly and enhance the performance of TIADC efficiently, at the same time, reduces the complexity and calculation.