An Improved All-Digital Background Calibration Technique for Channel Mismatches in High Speed Time-Interleaved Analog-to-Digital Converters

Abstract

The time-interleaved analog-to-digital converters (TIADCs), performance is seriously affected by channel mismatches, especially for the applications in the next-generation communication systems. This work presents an improved all-digital background calibration technique for TIADCs by combining the Hadamard transform for calibrating gain and timing mismatches and averaging for offset mismatch cancellation. The numerical simulation results show that the proposed calibration technique completely suppresses the spurious images due to the channel mismatches at the output spectrum, which increases the spurious-free dynamic range (SFDR) and signal-to-noise and distortion ratio (SNDR) by 74 dB and 43.7 dB, respectively. Furthermore, the hardware co-simulation on the field programmable gate array (FPGA) platform is performed to confirm the effectiveness of the proposed calibration technique. The simulation and experimental results clarify the improvement of the proposed calibration technique in the TIADC’s performance.

A Digital Timing-Mismatch Calibration Technique for Time-Interleaved ADCs Based on a Coordinate Rotational Digital Computer Algorithm

“…All of these mismatch errors have a great impact on the dynamic performance of a TIADC, affecting factors such as the SNDR and the SFDR. The timing mismatch, as the most influential factor [5][6][7][8][9], requires more sophisticated calibration methods because of the input's frequency dependence and nonlinearity. Since the TIADC architecture was proposed in 1980 [10], calibration techniques of timing mismatch, including estimation algorithms and compensation methods, have been the focus of attention.…”

Enabling Fine Sample Rate Settings in DSOs with Time-Interleaved ADCs

“…Time interleaved structures are complemented with a digital circuit that combines the sample streams and carries out further real-time operations to produce a calibrated response and/or enable different acquisition modes. The most common approaches exploit polyphase filters, which are suitable to manage parallel data streams [ 33 , 34 , 35 ]. Unfortunately, they lack however of adequate reconfigurability features to enable fine sample rate selection capabilities.…”