Group-delay-insensitive linear equaliser for reducing eye-skew in PAM-4 receivers
A novel group-delay-insensitive linear equaliser (GDILE) is proposed to reduce the eye-skew in four-level pulse amplitude modulation (PAM-4) receivers. With a cross-coupled positive-feedback degeneration network, the proposed GDILE employs additional pole and zero into its transfer function to reduce the group-delay variation with frequency. Simulation results shows a 40 Gbit/s PAM-4 receiver that employs a GDILE that can reduce the eye-skew by 73% compared with the conventional linear equaliser with a modest increase of power consumption.
