||FreeBSD General Commands Manual
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] bitmapfile
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,
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 documentation - even
spelling errors and typos, please let me know.
atlc is a finite difference program that is used to calculate the
properties of a two-conductor electrical transmission 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 (anything else). Pure white is assumed to be a vacuum
dielectric, 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 -S
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 program. The default is
0.0001, meaning two separate iterations must be within 01% for the program to
stop iterating. Setting 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 COLOURS below
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 version 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 convergence method, which is generally not a good idea.
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
possible 16777216 colours can be defined precisely by the stating the exact
amount of red, green and blue, as in:
Adds 'prefix', which is usually a directory name, in front of the output
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 (see
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 directional couplers.
The following dielectrics are reconised by atlc:
white 255,255,255 or 0xFFFFFF as Er=1.0 (vacuum)
Here are a few examples of the use of atlc. Again, see the html documentation in
atlc-X.Y.Zocs 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.
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 test purposes)
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 option.
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
ex_3 % atlc -v coax2.bmp
Original bitmap file. Must be 24-bit colour uncompressed.
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.
X-component of E-field as a bitmap. Red=+dV/dx, blue =-dV/dx
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
atlc(1) create_bmp_for_circ_in_circ(1) create_bmp_for_circ_in_rect(1)
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
Visit the GSP FreeBSD Man Page Interface.
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