## NAME

         create_bmp_for_circ_in_circ - bitmap generator for  circular
         conductor inside circular conductor (part of atlc)

## SYNOPSIS

         create_bmp_for_circ_in_circ  [options...  ]   D   d   O   Er
         filename.bmp

## WARNING

         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
         /usr/local/share/atlc/docs/html-docs/index.html
         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.

## DESCRIPTION

         create_bmp_for_circ_in_circ is a pre-processor for atlc, the
         finite difference program that is used to calculate the pro-
         perties of a two and three conductor electrical transmission
         line    of    arbitrary    cross    section.   The   program
         create_bmp_for_circ_in_circ is used as a fast  way  of  gen-
         erating  bitmaps  (there  is  no need to use a graphics pro-
         gram), for a circular conductor inside a circular  conductor
         (coaxial conductors), like this:

                             *****************
                         ****                 ****
                      ****    <-----d------>     ****
                    ***            *****            ***
                  ***           ***********           ***
                ***            *************            ***
               ***            ***************            ***
              ***      ^      ***************             ***
             ***       |      ***************              ***
            ***        |       *************                ***
            **         O        ***********                  **
           ***         |            ***                      ***
           **          |                                      **
           *<------------------------D------------------------>*
           **                                                 **
           **                                                 **
           **                                                 **
           ***                                               ***
            **                                               **
            ***                                             ***
             **                                             **
              **                                           **
               **                                         **
                ***                                     ***
                 ****                                 ****
                   ****                             ****
                     *****                       *****
                        ******               ******
                            *******************
                                    ***

         The parameter 'D' is the inner dimensions of the outer  con-
         ductor and 'd' is the outer diameter of the inner conductor.
         The inner conductor is offset 'h' from  the  centre  of  the
         outer conductor. The whole region is surrounded by a dielec-
         tric of relative permittivity 'Er'.

         The bitmap is printed to 'outfile.bmp' -  the  last  command
         line argument.

         The bitmaps produced by create_bmp_for_circ_in_circ are  24-
         bit bit colour bitmaps, as are required by atlc.

         The permittivities of the  dielectric  'Er'  determines  the
         colours  in the bitmap. If Er is 1.0, 1.006, 2.1, 2.2, 2.33,
         2.5, 3.3, 3.335, 3,7, 4.8, 10.2  or  100,  then  the  colour
         corresponding  to that permittivity will be set according to
         the colours defined in COLOURS below. If Er is  not  one  of
         those  permittivities, the region of permittivity Er will be
         set to the colour 0xCAFF00. The program atlc does  not  know
         what  this  permittivity  is, so atlc, must be told with the
         command line option -d, as in example 4 below.

## OPTIONS

         -b bitmapsize
         is used to set the size of the bitmap, and so  the  accuracy
         to  which  atlc is able to calculate the transmission line's
         properties. The default value for 'bitmapsize'  is  normally
         4,  although  this  is set at compile time. The value can be
         set anywhere from 1 to 15, but more than 8 is  probably  not
         sensible.

         -f outfile
         Set the output filename. By default, the bitmap is  sent  to
         stdout,  but  it *must* be sent to a file, with this option,
         or as described above.

         -v
         Causes create_bmp_for_circ_in_circ to  print  some  data  to
         stderr. Note, nothing extra goes to standard output, as that
         is expected to be redirected to a bitmap file.

## COLOURS

         The 24-bit bitmaps that atlc expects, 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, turquoise,  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 and example 5 below).
         The following conductors are reconised by atlc:
         red    = 255,000,000 or 0xff0000 is the live conductor.
         green  = 000,255,000 or 0x00ff00 is the grounded conductor.
         blue   = 000,000,000 or 0x000000 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 program gets extended to analyse
         directional couplers.

         The following dielectrics are reconised by atlc and  so  are
         produced by create_bmp_for_circ_in_circ.

         white     255,255,255 or 0xFFFFFF as Er=1.0   (vacuum)
         pink      255,202,202 or 0xFFCACA as Er=1.0006 (air)
         blue      000,000,255 or 0x0000FF 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)
         Turquoise 026,239,179 or 0x1AEFB3 as Er=4.8   (glass PCB)
         Dark gray 142,142,142 or ox696969 as Er=6.15  (duroid 6006)
         L. gray   240,240,240 or 0xDCDCDC as Er=10.2  (duroid 6010)

## NOTE

         Although create_bmp_for_circ_in_circ is  used  for  circular
         inner and outer conductors, the outside of the outer conduc-
         tor is drawn as a square. This is for convenience and  makes
         no  difference  to  the  calculations.  The inside is of the
         outer conductor is drawn as a circle.

## EXAMPLES

         Here   are    a    few    examples    of    the    use    of
         create_bmp_for_circ_in_circ.  Again, see the html documenta-
         tion in atlc-X.Y.Z/docs/html-docs/index.html for more  exam-
         ples.

         1) In the first example, the outer conductor has  an  inside
         diameter  of 12 units (inches, mm, feet etc.), the inner has
         an outside diameter of 3.9 units.  The inner is placed  cen-
         trally (h=0) and the dielectric is vacuum (Er=1.0).
         % create_bmp_for_circ_in_circ 12 3.9 0 1.0 coaxial_1.bmp
         % atlc coaxial_1.bmp
         atlc will indicate the correct  value  of  impedance  to  be
         67.3667  Ohms,  whereas an exact analysis will show the true
         value to be 67.4358 Ohms, so atlc has an error of 0.102%.

         2) In this second example, the conductor sizes are the sames
         as  in  example  1,  but the inner is located 3.5 units off-
         centre and the dielectric has a relative permittivity of 2.1
         (Er  of PTFE) The output is sent to a file not_in_centre.bmp
         which is then processed by atlc
         %    create_bmp_for_circ_in_circ    12    3.9    3.5     2.1
         not_in_centre.bmp
         % atlc not_in_centre.bmp
         The impedance of this is theoretically  24.315342  Ohms,  as
         create_bmp_for_circ_in_circ  will  calculate for you. atlc's
         estimate is 24.2493 Ohms, an error of only -0.271 %.

         3) In the third  example  the  bitmap  is  made  larger,  to
         increase  accuracy,  but  otherwise this is identical to the
         previous one.
         %   create_bmp_for_circ_in_circ   -b8   12   3.9   3.5   2.1
         bigger_not_in_centre.bmp
         % atlc bigger_not_in_centre.bmp
         This time atlc will take much longer to calculate Zo,  since
         the  bitmap  is  larger  and so it needs to do more calcula-
         tions. However, the final result should be more accurate. In
         this  case,  the  result  reported is 24.2461 Ohms, an error
         that's marginally smaller than before at  0.285  %.   It  is
         possible  there  may be something to be gained by decreasing
         the cutoff at larger grids, so this is  being  investigated.
         However,  errors  almost always below 0.25 %, no matter what
         is being analysed.
         In the fourth example, a material with a relativity  permit-
         tivity  7.89  of  is  used. There is no change in how to use
         create_bmp_for_circ_in_circ, but since this permittivity  is
         not  one  of  the  pre-defined values (see COLOURS), we must
         tell atlc what it is.  The colour will be set an olive green
         one, with a hexacidcal representation of red=0xCA, blue=OxFF
         and green = 0x00. This just happens to be the default colour
         used when the permittivity is unknown. So atlc must be given
         this information, like thisL
         % create_bmp_for_circ_in_circ 23 9 0 7.89 an_odd_er.bmp
         % atlc -d CAFF00=7.89 an_odd_er.bmp

         This has a theoretical impedance of 20.041970 Ohms, but atlc
         version  3.0.1  will calculate it to be 20.0300, an error of
         -0.058 % !!! If you look at the file  an_odd_er.bmp  with  a
         graphics  package,  you will see there are 3 colours in it -
         the red inner conductor, the green outer and an  olive-green
         dielectric.

## SEE ALSO

         atlc(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_cen_in_rect_coupler(1)
         create_bmp_for_rect_in_circ(1)
         create_bmp_for_rect_in_rect(1)
         create_bmp_for_stripline_coupler(1)
         create_bmp_for_symmetrical_stripline(1)
         design_coupler(1)
         find_optimal_dimensions_for_microstrip_coupler(1) readbin(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