atlc's
Frequently asked questionsatlc
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not be a good idea?atlc
calculate the loss of a transmission line?atlc
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released? atlc
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calculate the impedance of any transmission line?atlc
calculate the impedance of such a transmission line, with the two dielectrics - vacuum and the fibreglass PCB.atlc
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need to know the dimensions of transmission lines?atlc
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is a computer programme designed for finding the properties (characteristic impedance, inductance per m, capacitance per metre, velocity factor, electric field distribution) of any transmission line with 2 or 3 conductors (i.e. a normal line or coupler). It used the finite difference method to determine these properties, so while slower than other methods, can handle any cross section.atlc
?Electrical characteristics L=145.5810 nH/m C=76.4283 pF/m Zo= 43.6441Ohms v= 299792458.010503 m/s |
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Total electric field (white is higher) |
x-directed E-field, Red in +x direction, blue in -x direction. |
y-directed E-field. Red in +y direction, blue in -y direction. |
atlc
not be a good idea?atlc
. But generally, atlc is designed for the cases where there are no analytical results.atlc
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. Floating point support in hardware is strongly recommended. Hence a 486 or better PC is really needed, or perhaps a 386 with 387 floating point processor. Given the programme is fairly time consuming, I would suggest at least a 100 MHz machine, preferably a lot more. The programme should compile easily, as only the standard maths library is needed. If you have multiple processors, you can add multi-threaded support. If you wish to do this, you will need to have pthreads installed. atlc
has been tested on a 350 MHz Pentium II PC with Red Hat Linux (release 6.1, kernel 2.2.12-98), a Sun SPARCstation 20 with Solaris 8 and 4 x 125 MHz HyperSPARC CPUs and a Sun Ultra 60 with dual 300 MHz processors. All CPUs were used on the Sun workstations. I've not tested multi-processor support on any other machine.atlc
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was written and is maintained by Dr. David Kirkby, drkirkby@ntlworld.comatlc
released ?atlc
? atlc
? % gzip -d atlc-X.Y.Z.tar.gzWhere X.Y.Z is the version
% tar xv atlc-X.Y.Z.tar % cd atlc-X.Y.Z % ./configure % make % cd src % ./tests % su # make installBy default, the binaries are installed in /usr/local/bin and the man pages in /usr/local/man. I've not determined how to use autoconf or automake to put the html documents somewhere sensible, so you will have to do that by hand. You will need root access to install the files in /usr/local, but if you wish to install them elsewhere, you can do
% ./configure --prefix=~ % make % cd atlc-X.Y.Z. % make installto install off your home directory.
% configure --with-mp % make % su # make installThe programme must be configured first without threaded support, as the tests will not complete proplerly otherwise. I would suggest you test a few examples without threaded support too, as this has not been tested on many machines. On my old quad CPU Sun SPARCstation 20, using a large bitmap (for best accuracy) results in about 80% utilisation of my 4 cpus, resulting in results that are around 2.4x faster than on one cpu. On my current machine, a dual processor Sun Ultra 60, it runs about 1.7x faster on 2 cpus. On small bitmaps, there is little or no advantage in running on multiple CPUs.
atlc
calculate the impedance of the transmission line with the two dielectrics - vacuum and the fibreglass PCB. atlc
is conveniently configured for the following dielectric constants - 1.0, 2.1 (PTFE), 2.3 (RT duriod 5880), 2.33 (Polyethylene), 2.5 (polystyrene), 3.3 (PVC), 3.335 (epoxy resin), 4.8 (fibreglass), 6.15 (duriod 6006) and 10.2 (duroid 6010). Any other permittivity can be defined, but needs slightly more effort in doing so.atlc
from 4.0.0 onwards are able to calculate an even-mode impedance Zeven and an odd-mode impedance Zodd Zodd. However, directional couplers support is not complete yet, as you can not do multiple dielectrics or even a single dielectric other than vacuum.. .atlc
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works is very accurate. Errors of less than 0.3% are typical, and largest error every recorded is under 1%. The problem is that achieving such accuracy is very time consuming. Few people need results more accurate than 1%, in which case the run-times should be only a few minutes at most. atlc
work? atlc
uses a method known as finite differences. A paper describing the theory of this was published in the amateur radio journal QEX See: Finding the characteristics of Arbitrary transmission lines, D. Kirkby, QEX, December 1996, page 3-10. You can download a copy if you wish, or there should be a a local copy rect_in_rect
is for this purpose, as it can automatically draw bitmaps for a rectangular conductor inside another rectangular conductor, like the following transmission line. rect_in_rect
. atlc is written and supported by Dr. David Kirkby (G8WRB) It it issued under the GNU General Public License