Calibration of gain and time mismatches for time-interleaved ADCs based on digital filter bank

Abstract

As we known, time-interleaved analog-to-digital converters (TIADC) is effective on increasing the system sampling rate. But the gain, offset and time mismatches among the sub-ADCs introduce undesirable noise into the system and degrade the overall performance seriously. This paper describes a post calibration method with digital filter banks to remove the gain and time mismatch errors. These digital filters, whose coefficients are according to weighted least square (WLS) criteria, are carried out with poly-phase structure. Simulation results show that this method can significantly improve the spurious free dynamic range (SFDR) and signal to noise ratio (SNR) of TIADC system.