1NGMULTIDEC(1) General Commands Manual NGMULTIDEC(1)
2
3
4
6 ngmultidec - make ngpice sub-circuit for coupled transmission lines
7
9 ngmultidec [ options... ]
10
12 ngmultidec writes an ngspice input file to standard output which
13 describes a sub-circuit for coupled lines using uncoupled simple lossy
14 lines.
15
16 Each generated subcircuit models a 4-conductor transmission line with
17 the following parameters: length l, line capacitance c, line resistance
18 r, line conductance g, inductive_coeff_of_coupling k, inter-line capac‐
19 itance cm, length l. Derived parameters are: lm, ctot. The values of
20 l, c, the model name, the number of conductors and the length of the
21 line must be specified.
22
23 It is important to note that the model is a simplified one - the fol‐
24 lowing assumptions are made: 1. The self-inductance l, the self-capaci‐
25 tance ctot (note: not c), the series resistance r and the parallel
26 capacitance g are the same for all lines, and 2. Each line is coupled
27 only to the two lines adjacent to it, with the same coupling parameters
28 cm and lm. The first assumption implies that edge effects have to be
29 neglected. The utility of these assumptions is that they make the sL+R
30 and sC+G matrices symmetric, tridiagonal and Toeplitz, with useful con‐
31 sequences (see the paper referenced below).
32
33 It may be noted that a symmetric two-conductor line is represented
34 accurately by this model.
35
36 Standard C language scientific (exponent) notation may be used for
37 options' numeric values.
38
40 -osubcircuit_name
41 Set the subcircuit name
42
43 -lline_inductance
44 Set the line inductance.
45
46 -cline_capacitance
47 Set the line capacitance.
48
49 -rline_resistance
50 Set the line resistance.
51
52 -gline_conductance
53 Set the line conductance.
54
55 -kinductive_coefficient_of_coupling
56 Set the value of the inductive coefficient of coupling, whose
57 absolute value k must be less than 1.0.
58
59 -xline-to-line-capacitance
60 Set the line-to-line capacitance.
61
62 -Llength
63 Set the length of the line.
64
65 -nnumber
66 Set the number of conductors.
67
68 -u Write a usage message to standard error.
69
71 ngmultidec -n4 -l9e9 -c20e-12 -r5.3 -x5e12 -k0.7 -otest -L5.4 >
72 test.cir
73
75 Efficient Transient Simulation of Lossy Interconnect,
76 J.S. Roychowdhury and D.O. Pederson,
77 Proceedings of the Design Automation Conference,
78 pp. 740-745.
79 1991.
80 http://portal.acm.org/citation.cfm?doid=127601.127762
81
82 ngnutmeg(1), ngproc2mod(1), ngsconvert(1), ngspice(1), nghelp(1).
83
84
85
86 ngpice NGMULTIDEC(1)