NAME

       ngmultidec - make ngpice sub-circuit for coupled transmission lines

SYNOPSIS

       ngmultidec [ options...  ]

DESCRIPTION

       ngmultidec  writes  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: length l,
       line  capacitance  c,  line  resistance  r, line conductance g, inductive_coeff_of_coupling k, inter-line
       capacitance cm, length l.  Derived parameters are: lm, ctot.  The values of l, 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_name
              Set the subcircuit name

       -lline_inductance
              Set the line inductance.

       -cline_capacitance
              Set the line capacitance.

       -rline_resistance
              Set the line resistance.

       -gline_conductance
              Set the line conductance.

       -kinductive_coefficient_of_coupling
              Set the value of the inductive coefficient of coupling, whose absolute value k must be  less  than
              1.0.

       -xline-to-line-capacitance
              Set the line-to-line capacitance.

       -Llength
              Set the length of the line.

       -nnumber
              Set the number of conductors.

       -u     Write a usage message to standard error.

EXAMPLE

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

SEE ALSO

       Efficient Transient Simulation of Lossy Interconnect,
       J.S. Roychowdhury and D.O. Pederson,
       Proceedings of the Design Automation Conference,
       pp. 740-745.
       1991.
       http://portal.acm.org/citation.cfm?doid=127601.127762

       ngnutmeg(1), ngproc2mod(1), ngsconvert(1), ngspice(1), nghelp(1).

                                                     ngpice                                        NGMULTIDEC(1)