Singly Terminated & Bi-Transversal Transmission Line Filters for High Speed Adaptive Equalization

We show that transmission line based FIR filters built using singly terminated delay lines can perform as well as travelling-wave structures (with a fraction of the power dissipation), provided resistive shunt compensation is employed to cancel the effects of series loss in the transmission lines. The problem of an unwieldy aspect ratio of a transversal filter when laid out on an integrated circuit is avoided by employing a class of structures called bi-transversal filters. The electrical equivalence between singly-terminated and bi-transversal filters is proved, and we conclude that these form excellent candidates for the LMS algorithm based adaptive equalization at gigabit speeds.