An adaptive pre-emphasis technique with opposite directional training

This paper presents a novel adaptive pre-emphasis technique for half-duplex communication in asymmetric systems between electronic control units (ECUs) and automotive actuators. Both an adaptive decision feedback equalizer (DFE) and a DFE-like pre-emphasis circuit are implemented in only ECU side in order to compensate frequency dispersion of the automotive-grade harness. By transmittng the traning pattern from the actuator, the coefficients of both DFE and DFE-like pre-emphasis circuit are determined, providing the same equalization characteristics. The proposed pre-emphasis technique enables the actuator to receive already equalized signals without equalization circuit in it. Our simulation results demonstrate more than 200% improvement of the eye openinig for 400Mbps communication with a 5-m harness of more than 10-dB dispersion at the Nyquist frequency.