Crosstalk Analysis Of Lossy And Nonuniform Transmission Lines In Time And Frequency Domains

As a medium of high-speed signal transmission between devices,field-line coupling inevitably occurs between wire harnesses.If the crosstalk can be predicted effectively and the mechanism of the influencing factors is known,the corresponding measures can be taken in time to achieve a certain degree of interference suppression.Crosstalk research in the field of field-line coupling is mostly based on ideal conditions.The calculation of crosstalk has great limitations.The main contents of this paper are as follows:1.Establish a lossy non-uniform transmission line model which is more suitable for practical application,especially the new twisted pair crosstalk model.2.A new method for calculating transmission line distribution parameters in lossy and nonuniform media is proposed,which is called hierarchical series method.3.In the frequency domain steady state interference,the chain parameter matrix method is used to solve the frequency domain steady state interference at the beginning and the end of the transmission line.Based on the cascade method,the chain parameter matrix of the crosstalk model of lossy twisted pair is derived.The steady-state expressions of near-end crosstalk the far-end crosstalk are deduced according to the load conditions.4.The FDTD algorithm is used to solve the transient interference of transmission lines with constant loss and frequency-varying loss.By combining FDTD with recursive convolution and Prony approximation,the voltage and current iteration formulas of frequency-varying loss transmission lines are derived.Frequency-varying loss includes not only the frequency-varying internal impedance caused by skin effect,but also the frequency-varying ground impedance caused by the loss of earth conductivity.Finally,the crosstalk simulation of several models on the ground and in the shielding layer is carried out.The theory presented in this paper can be applied to the prediction of crosstalk in high-speed data transmission system,which provides some theoretical guidance for further research.