Scattering-based nonlinear macromodels of high-speed differential drivers

This paper introduces a scattering-based nonlinear macromodeling framework for high-speed differential drivers. Using an industrial test case, we show that the proposed scattering formulation enables more accurate and robust model identification with respect to standard voltage-current representations. The combination of proposed driver models with a Waveform Relaxation solver allows accurate and efficient transient channel simulation, including nonlinear and dynamic termination effect

Multi-channel P-ISAR grating lobes cancellation

The coherent combination of multiple channels for ISAR imaging purposes in passive radar systems is required in order to achieve a good range resolution. Passive ISAR may provides a suitable means to implement automatic target classification (ATC) and automatic target recognition (ATR). The range resolution is related to the transmitted signal bandwidth, therefore adjacent and non adjacent multi-channel signals should be exploited to obtain a wide band signal. This paper addresses the grating lobes issue that rises when a wide band signal with bandwidth gaps is obtained by adjoining multiple adjacent DVB-T channels. A cancellation technique based on the spatially variant apodization (SVA) technique is proposed. Results both on simulated and real data are provided.</p

Macromodel-Based Iterative Solvers for Simulation of High-Speed Links With Nonlinear Terminations

Data transmission on high-speed channels may be affected by several undesired effects, including coupling from nearby interconnects, dispersion, losses, signal reflections from terminations and from internal discontinuities, and nonlinear/dynamic effects of drivers and receivers. The latter are often neglected, leading to very fast solvers, whose results may however be questionable when driver/receiver nonlinearities are important. This paper presents a framework for the transient analysis of complex high-speed channels with arbitrary nonlinear termination circuits. The approach is based on decoupling channel and terminations through a scattering-based Waveform Relaxation (WR) formulation. The channels are here cast as delay-rational macromodels, which are solved in discrete time domain through fast delayed recursive convolutions. The terminations can be either arbitrary circuits, solved by SPICE, or nonlinear behavioral macromodels, which are here formulated in discrete-time scattering representations. In order to overcome the known convergence issues of standard WR methods, we apply here more general iterative solution schemes, such as GMRES and BiCGSTAB, integrated into inexact Newton iterations, obtaining a set of numerical schemes with guaranteed convergence. The excellent performance of the proposed approach is illustrated on a large set of benchmarks