Backpropagation Based Background Compensation of TI-DAC Errors in High-Speed Transmitters

Abstract

This work proposes a new digital adaptive background architecture to compensate impairments in ultra-high-speed time-interleaved digital-to-analog converters (TI-DAC) used in digital communication transmitters. Mismatches between the sub-DACs in high-speed TI-DACs (which are caused by process, voltage, and temperature variations) significantly degrade the performance of high-speed digital communication systems. The key ingredients of the new background compensation technique are (i) the multiplexed impairment equalizer (MIE) and (ii) the error backpropagation (BP) algorithm used to adapt the coefficients of the MIE. Simulations show that TI-DAC impairments can be accurately compensated, eliminating their detrimental effect on the performance of the digital communication system. This fact in combination with the low implementation complexity make the proposed compensation algorithm a good candidate to be adopted in high-speed commercial devices (e.g., coherent optical transceivers).