Mixed-signal equalization architectures for printed circuit board channels

This paper develops mixed signal equalization solutions for gigabit communications in printed circuit boards (PCBs). The PCB channel, composed by vias and interconnects, distorts and produces signal reflections that deteriorate quality of high speed data transmission. Analog signal processing architectures are necessary to combat the ISI effects introduced by the channel since high speed A/D conversion is a very expensive solution. A novel system description and circuit-level architecture that performs mixed-signal feedforward and feedback equalization in the transmit end is introduced. System level simulations show how this combined FF-FB transmit equalizer outperforms the conventional pre-emphasis structures presented in previous works, with a reasonable compromise in circuit area.