## Radio Math Stuff

### Some useful (and not so useful) math for radio applications

Matrix Inversion - complex admittance and impedance matrices (links to spreadsheets and Matlab stuff)

Exponential Integrals - Sine and Cosine integrals pop up in mutual impedance calculations

Euler's number (shows up in a variety of places)

Bessel functions - patterns of uniformly illuminated circular apertures (and FM modulation, too)

Wye/Delta (or T/Pi) transformations

Transmission line equations (including hyperbolic functions)

Transmission line impedance formulae (particularly microstrip, etc.) tlz.htm

Two Port Matrix representations (including conversions between them)

### Other useful math stuff

A great set of matrix routines for use in Excel. They do complex math, create admittance matrices, etc. It's just an Excel add-in that doesn't make ANY changes in your configuration. Delete the files and it's gone. http://digilander.libero.it/foxes/index.htm

Here are the zip files:
The Excel Add-in http://digilander.libero.it/foxes/matrix18.zip
Documentation: http://digilander.libero.it/foxes/MatrixTutorial1.zip (This one's just a big 200+ page pdf after expanding it)

If you use these, you'd better learn about entering matrix functions in Excel (Ctrl, Shift, Enter). It's in the first few pages of the tutorial, above, and in the help file with the add in, but takes getting used to.

More Excel: XLZIZL is a spreadsheet that analyzes transmission lines and matching components by AC6LA. Extremely useful. Kind of slow to download because it's at qsl.net, but worth the time: http://www.qsl.net/ac6la/xlzizl.html

radio/math/index.htm - 10 Jan 2005 - Jim Lux