Provided by: ngspice_23-1_amd64

**NAME**

ngmultidec - make ngpice sub-circuit for coupled transmission lines

**SYNOPSIS**

ngmultidec[options... ]

**DESCRIPTION**

ngmultidecwrites an ngspice input file to standard output which describes a sub-circuit for coupled lines using uncoupled simple lossy lines. Each generated subcircuit models a 4-conductor transmission line with the following parameters: lengthl, line capacitancec, line resistancer, line conductanceg, inductive_coeff_of_couplingk, inter-line capacitancecm, lengthl. Derived parameters are:lm,ctot. The values ofl,c, the model name, the number of conductors and the length of the line must be specified. It is important to note that the model is a simplified one - the following assumptions are made: 1. The self-inductance l, the self-capacitance ctot (note: not c), the series resistance r and the parallel capacitance g are the same for all lines, and 2. Each line is coupled only to the two lines adjacent to it, with the same coupling parameters cm and lm. The first assumption implies that edge effects have to be neglected. The utility of these assumptions is that they make the sL+R and sC+G matrices symmetric, tridiagonal and Toeplitz, with useful consequences (see the paper referenced below). It may be noted that a symmetric two-conductor line is represented accurately by this model. Standard C language scientific (exponent) notation may be used for options' numeric values.

**OPTIONS**

-osubcircuit_nameSet the subcircuit name-lline_inductanceSet the line inductance.-cline_capacitanceSet the line capacitance.-rline_resistanceSet the line resistance.-gline_conductanceSet the line conductance.-kinductive_coefficient_of_couplingSet the value of the inductive coefficient of coupling, whose absolute valuekmust be less than 1.0.-xline-to-line-capacitanceSet the line-to-line capacitance.-LlengthSet the length of the line.-nnumberSet the number of conductors.-uWrite a usage message to standard error.

**EXAMPLE**

ngmultidec-n4-l9e9-c20e-12-r5.3-x5e12-k0.7-otest-L5.4>test.cir

**SEE** **ALSO**

EfficientTransientSimulationofLossyInterconnect, J.S. Roychowdhury and D.O. Pederson, Proceedings of the Design Automation Conference, pp. 740-745. 1991.http://portal.acm.org/citation.cfm?doid=127601.127762ngnutmeg(1),ngproc2mod(1),ngsconvert(1),ngspice(1),nghelp(1). ngpice NGMULTIDEC(1)