Multiconductor Transmission Line Models for Modal Transmission Schemes

We investigate modal transmission schemes used to reduce echo and internal crosstalk in a multichannel link using an untransposed multiconductor interconnection. The core of such a modal transmission scheme is an appropriate multiconductor transmission line (MTL) model of the interconnection. The standard theory of modal signaling, which emphasizes modal voltages, modal currents, and associated eigenvectors is summarized. Then, we present new results of MTL theory: three theorems on generalized associated eigenvectors and two high-frequency approximations. These results are needed to explain an assumption used in some modal transmission schemes.