This program NetCalc is broadly based on NETCALC - an RF Impedance Calculator by Ian White, G3SEK.
The concepts and command names follow those in NETCALC, but the coding and design of this program are entirely new.
This program can also display impedances on a diagram similar to the well-known Smith Chart.
The L-section code is based on a PERL program by Claude Frantz.
NETCALC is available from the above link and can be executed on an IBM PC under various versions of the Microsoft Windows Operating System. Indeed, I have also used it under SoftWindows on an Apple iMac.
However, I wanted a version that would run native on a Macintosh as well as on a PC and thought that writing and testing such a program would teach me a lot about network analysis and Smith Charts.
Some time ago, I produced HyperCard and REALbasic® versions of NetCalc.
This version is a Konfabulator Widget.
Here is a view of the program when it first opens.
Data is entered via the panel at the top right and transfered to the X register by use of the + and || buttons.
Operations on the X (and Y) register(s) are performed using the buttons at the bottom right. The command names are the same as those in NETCALC, so you should read the NETCALC instructions before attempting to use the program.
The X and Y registers appear in the panel at the top left. The X register is also shown in parallel form in the P register.
The environment parameters are entered in the middle left panel, apart from Z0 which must first be entered via the data panel and transferred from X to Z0 using the Z0 button. Complex characteristic impedances can be entered if desired.
Many of the circuit parameters are recomputed at every operation. Others are computed as required.
The panel at the bottom left displays the normalised value of X in the N register and the reflection coefficient (in polar form) in the rho register. The VSWR is displayed in the Z register, which is also used as a general display register.
There are buttons to compute the modulus of X and of N, and four buttons to produce a rudimentary display similar to that on a Smith Chart.
R + L X -> Y, R + L -> X R || L X -> Y, R || L -> X R + x X -> Y, R + x -> X R || x X -> Y, R || x -> X R + C X -> Y, R + C -> X R || C X -> Y, R || C -> X
Rn X -> Y, Rn -> X
E X <=> Y
+ X + Y -> X, 0 -> Y
|| X || Y -> X, 0 -> Y
?n Rn -> Z
J X* -> X
* X * Factor -> X
/ X / Factor -> X
Mn X -> Mn
Z0 X -> Z0
T X + T(Z0, F, V, length) -> X
C Y -> X, 0 -> Y
Q x/r -> Z, where X = r + jx
X if x >= 0, L = x/(2πF) -> Z, where X = r + jx
if x < 0, C = (-2πF)*x -> Z, where X = r + jx
L L(X, Z0, F, V) -> Z
W (1 +|rho|)/(1 - |rho|) -> Z,
where rho = ((X/Z0) - 1)/((X/Z0) + 1)
LS Displays L-sections matching the load X to the real part of Z0
|X| |X| -> Z |N| |X/Z0| -> Z
The CIRCLE, POINT, S and CS buttons are used as follows:
Here is a view of a chart:
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Wednesday, August 29, 2007.