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)