atlc - an Arbitrary Transmission Line Calculator


     atlc  [-v] [-c cutoff] [-d rrggbb=Er]  [-F  appendfile]  [-i
     factor] [-p threads] [-r rate_multiplier] bitmapfile


     This man page is not a complete set  of  documentation.  See
     the  html  files for more complete information. So far, I've
     not managed to install the html files  into  /usr/local,  so
     you  will  have  to  look into the atlc-X.Y.Z/docs/html-docs
     directory for them.


     atlc is a finite difference programme 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 propogation 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 million colour) uncompressed 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 diferent meanings. See COLOURS
     below for precise definitions of the colours.


     -c cutoff
     Sets the convergence criteria of the finite difference  pro-
     gramme.  The  default is 0.0001, meaning two separate itera-
     tions must be within 01% for the programme to  stop  iterat-
     ing.  Setting  to a smaller positive number gives more accu-
     racy, 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

     -F appendfile
     Causes the results to be  appended  to  a  file  appendfile,
     which  will  be  a text file.  If the -v option is selected,
     intermediate results will go there too.

     -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 darken.

     -t threads
     tells atlc to run using that number  of  threads,  to  speed
     calculation.  This option is only valid if atlc was compiled
     with the --with-mp option to configure. The Pthreads library
     ()  must  be  installed in order to compile with support for
     more than one CPU. Generally, setting the number of  threads
     to the number of cpus is a good idea, but it is worth exper-
     imenting. The number can be changed permanently  by  editing
     the parameter MAX_THREADS in definitions.h.

     -r ratemultiplier
     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 belived 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.

     makes the output more verbose/talkative.


     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 i16777216 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, terquiose,  sandy,  brown,  gray
     etc  may mean slightly different things to different prople.
     This is not so with  atlc,  as  the  programme  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 not currently supported,
     but it will be used to indicate a negative conductor,  which
     will  be  needed  if/when  the  programme  gets  extended to
     analyse directional couplers.

     The following dielectrics are recognised by atlc and so  are
     produced by rect_cen_in_rect.

     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)
     Terquoise 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)


     Here are a few examples of the use of atlc. Again,  see  the
     html documentation in atlc-X.Y.Z9ocsl-docs for 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, 4.8, 6.15 or 10.2) could have been
     used in the bitmap, which would have been done with  one  of
     10  different  colours  (white  (0xFFFFFF)  for Er=1.0, pink
     (0xFFCACA) for 1.0006 etcin the  bitmap  file  coax2.bmp  No
     other  colour(dilectric)  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 dielectic 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 .bmp 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.


        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
     bitmapfile.txt Results, in a text file for easy reading.

     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.


     rect_cen_in_rect(1),    circ_in_circ(1).    rect_in_rect(1),
     circ_in_rect(1).      rect_in_circ(1),     readbin(1)    and
     sym_strip(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              - my home page          - ham radio pages

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