High-speed electrical backplane transmission using duobinary signaling

High-speed electrical data transmission through low-cost backplanes is a particularly challenging problem. We present for the first time a very effective approach that uses the concept of duobinary signaling to accomplish this task. Using a finite-impulse-response filter, we are able to compensate for the phase and amplitude response of the backplane such that the resulting frequency response of the channel is that of an ideal duobinary filter. At the output of the backplane, we use an innovative pseudodigital circuit to convert the electrical duobinary to binary. For 10-Gb/s data transmission, we demonstrate a bit error rate <10^-13 through electrical backplane traces up to 34 in in length on FR4. A full discussion of the concept, system architecture, and measured results are presented. Analysis is presented that compares and contrasts this approach to PAM-4 and standard nonreturn-to-zero signaling.