Hardware Implementation of Background Calibration Technique for TIADCs with Signals in Any Nyquist Bands

摘要

We investigate a novel fully digital background calibration technique to mitigate the gain and timing mismatches in Time-Interleaved Analog-to-Digital Converters (TIADCs) for the wideband bandlimited input signal at any Nyquist zones. The correction scheme is simple by subtracting the image signals from the distorted signal. The channel mismatch parameters are estimated based on out-of-band error estimation. Neither an additional reference channel and nor a pilot input are required in calibration. A four-channel 60dB SÒR TIADC operating at 2.7GHz is used in both simulation and experimental implementation to validate the proposed calibration technique. The SNDR improvement is 16dB for a multi-tone input occupied at the third Nyquist band. The calibration method is validated on Altera FPGA DE4 board. In a Hardware-In-the-Loop emulation framework, the synthesized circuit works effectively and utilizes a very little amount of the hardware resource in the FPGA chip.