atlc(1)                     General Commands Manual                    atlc(1)

       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, 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 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 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.
       -c cutoff
       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 takes longer.

       -d rrggbb=Er
       is used to indicate the colour 0xrrggbb in the bitmap is used to
       represent a material with permittivity Er. See also COLOURS below

       -i factor
       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

       -r ratemultiplier
       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

       -p prefix
       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 possible 16777216 colours can be defined precisely by
       the stating 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
       (see OPTIONS).
       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)
       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

       Here are a few examples of the use of atlc. Again, see the html
       documentation in atlc-X.Y.Zocsl-docs, the documentation on your system
       (normally at /usr/local/share/atlc/docs/html-docs/index.html ) or
       online at 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 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 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 =-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 files.

       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

       atlc(1) create_bmp_for_circ_in_circ(1) create_bmp_for_circ_in_rect(1)
       create_bmp_for_microstrip_coupler(1) create_bmp_for_rect_cen_in_rect(1)
       create_bmp_for_rect_in_circ(1) create_bmp_for_rect_in_rect(1)
       create_bmp_for_symmetrical_stripline(1) design_coupler(1)
       find_optimal_dimensions_for_microstrip_coupler(1) readbin(1)                - Home page       - 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

Dr. David Kirkby           atlc-4.4.2 10th Sept 2003                   atlc(1)