atlc - an Arbitrary Transmission Line Calculator
atlc [-C] [-s] [-S] [-v] [-c cutoff] [-d rrggbb=Er] [-i
factor] [-i prefix] [-t threads] [-r rate_multiplier] bit-
This man page is not a complete set of documentation - the
complexity of the atlc project makes man pages not an ideal
way to document it, although out of completeness, man pages
are produced. The best documentation that was current at the
time the version was produced should be found on your hard
drive, usually at
although it might be elsewhere if your system administrator
chose to install the package elsewhere. Sometimes, errors
are corrected in the documentation and placed at
http://atlc.sourceforge.net/ before a new release of atlc is
released. Please, if you notice a problem with the documen-
tation - even spelling errors and typos, please let me know.
atlc is a finite difference program that is used to calcu-
late the properties of a two-conductor electrical transmis-
sion line of arbitrary cross section. It is used whenever
there are no analytical formula known, yet you still require
an answer. It can calculate:
The impedance Zo (in Ohms)
The capacitance per unit length (pF/m)
The inductance per unit length (nF/m)
The velocity of propagation v (m/s)
The velocity factor, v/c, which is dimensionless.
A bitmap file (usually with the extension .bmp or .BMP) is
drawn in a graphics package such as Gimp available from
http://www.gimp.org. The bitmap file must be saved as a 24-
bit (16,777,216 colour) uncompqessed file. The colours used
in the bitmap indicate whether the region is a conductor
(pure red, pure green or pure blue) or a dielectric (any-
thing else). Pure white is assumed to be a vacuum dielec-
tric, but other colours have different meanings. See COLOURS
below for precise definitions of the colours.
print copyright, licensing and copying information.
Skip writing the Ex, Ey, E, V, U and Er bitmap (.bmp) files
Skip writing the Ex, Ey, E, V, U and Er binary (.bin) files
makes the output more verbose/talkative.
Sets the convergence criteria of the finite difference pro-
gram. The default is 0.0001, meaning two separate iterations
must be within 01% for the program to stop iterating. Set-
ting to a smaller positive number gives more accuracy, but
is used to indicate the colour 0xrrggbb in the bitmap is
used to represent a material with permittivity Er. See also
is used to lighten or darken the .bmp electric field profile
images produced by atlc. Set factor > 2 to lighten or
between 1 and 2 to darken.
Sets the parameter 'r' used internally when computing the
voltage at a point w,h. The default, which is (as of ver-
sion 3.0.0) 1.95, results in what is believed to be optimal
results. Setting to 1.0 will avoid the use of the fast con-
vergence method, which is generally not a good idea.
Adds 'prefix', which is usually a directory name, in front
of the output files.
The 24-bitmaps that atlc uses have 8 bits assigned to
represent the amount of red, 8 for blue and 8 for green.
Hence there are 256 levels of red, green and blue, making a
total of 256*256*256=16777216 colours. Every one of the pos-
sible 16777216 colours can be defined precisely by the stat-
ing the exact amount of red, green and blue, as in:
red = 255,000,000 or 0xff0000
green = 000,255,000 or 0x00ff00
blue = 000,000,255 or 0x0000ff
black = 000,000,000 or 0x000000
white = 255,255,255 or 0xffffff
Brown = 255,000,255 or 0xff00ff
gray = 142,142,142 or 0x8e8e8e
Some colours, such as pink, turquiose, sandy, brown, gray
etc may mean slightly different things to different people.
This is not so with atlc, as the program expects the colours
below to be exactly defined as given. Whether you feel the
colour is sandy or yellow is up to you, but if you use it in
your bitmap, then it either needs to be a colour reconised
by atlc, or you must define it with a command line option
red = 255,000,000 or 0xFF0000 is the live conductor.
green = 000,255,000 or 0x00FF00 is the grounded conductor.
blue = 000,000,255 or 0x0000FF is the negative conductor
All bitmaps must have the live (red) and grounded (green)
conductor. The blue conductor is used to indicate a negative
conductor, is needed when the program is used to analyse
The following dielectrics are reconised by atlc:
white 255,255,255 or 0xFFFFFF as Er=1.0 (vacuum)
pink 255,202,202 or 0xFFCACA as Er=1.0006 (air)
L. blue 130,052,255 or 0x8235EF as Er=2.1 (PTFE)
Mid gray 142,242,142 or 0x8E8E8E as Er=2.2 (duroid 5880)
mauve 255.000,255 or 0xFF00FF as Er=2.33 (polyethylene)
yellow 255,255,000 or 0xFFFF00 as Er=2.5 (polystyrene)
sandy 239,203,027 or 0xEFCC1A as Er=3.3 (PVC)
brown 188,127,096 or 0xBC7F60 as Er=3.335 (epoxy resin)
L. yellow 223,247,136 or 0xDFF788 as Er=3.7 (FR4 PCB)
Turquoise 026,239,179 or 0x1AEFB3 as Er=4.8 (glass PCB)
Dark gray 142,142,142 or 0x696969 as Er=6.15 (duroid 6006)
L. gray 240,240,240 or 0xDCDCDC as Er=10.2 (duroid 6010)
D. orange 213,160,067 or 0xD5A04D as Er=100.0 (mainly for
Here are a few examples of the use of atlc. Again, see the
html documentation in atlc-X.Y.Z9ocsl-docs, the documentation
on your system (normally at
/usr/local/share/atlc/docs/html-docs/index.html ) or online
at http://atlc.sourceforge.net for examples.
ex_1 % atlc coax2.bmp
This is a simple example (ex_1), in which the geometry of a
transmission line is defined in coax2.bmp. In this example,
only the predefined dielectrics (Er =1.0, 1.0006, 2.1, 2.2,
2.33, 2.5, 3.3, 3.335, 3.7, 4.8, 6.15 or 10.2) could have
been used in the bitmap, which would have been done with one
of 13 different colours. white (0xFFFFFF) for Er=1.0, pink
(0xFFCACA) for 1.0006 etc. No other colour (dielectric)
could have been used, since it was not specified with the -d
ex_2 % atlc -d f9e77d=2.43 somefile.bmp
In ex_2, a dielectric with Er=2.43 was wanted. A colour with
the RGB values of 0xF9E7&d was used. The -d option tells
atlc what Er this colour refers to.
ex_3 % atlc -v coax2.bmp
In ex_3, atlc has been instructed to print the results of
intermediate calculations to stdout. Normally, only the
final result is printed. Using -vv even more information may
be produced, but this is really of only use to the developer
of the project.
Original bitmap file. Must be 24-bit colour uncompressed.
X-component of E-field as a bitmap. Red=+dV/dx, blue =-
y-component of E-field as a bitmap. Red=+y, blue =-y
E-field, as E=sqrt(Ex^2+Ey^2).
Voltage as a bitmap, red= positive, blue =negative.
Bitmap showing the permittivity as a grayscale. Lighter
is a higher
In addition to the bitmaps, the data is also saved in binary
All the saved binary files (.bin's) are saved as a double
precision number for each of the pixels. The first double is
the top left, the last the bottom right. If the original
image has width W and height H, the saved binary files will
be W-1 by H-1.
All the saved bitmap files are 24-bit uncompressed, just
like the input files.
http://atlc.sourceforge.net - Home page
http://sourceforge.net/projects/atlc - Download area
atlc-X.Y.Z/docs/html-docs/index.html - HTML docs
atlc-X.Y.Z/docs/qex-december-1996/atlc.pdf - theory paper
atlc-X.Y.Z/examples - examples
Man(1) output converted with