42.8 Gbit/s PAM-4 data transmission over low-loss electrical backplane

Demonstrated is a record serial transmission rate of 42.8 Gbit/s by sending four-level pulse amplitude modulated (PAM-4) data over a low-loss Megtron 6 electrical backplane. The data is processed and equalised using early late gate timing recovery and a finite-impulse-response-based least-mean-squares equaliser. Bit error rate performance is reported over several different links.