PSK-31 and FFT's

[K1MDC]

Does anyone have any suggestions of where to get information about the mathematics necessary to create a PSK-31 program? I've been digging around and have found many complicated explanations that fast fourier transforms are used in signal processing, but very little in the way of exactly what you do with FFTs. I'm considering creating a new PSK-31 client, and I'd like to do the work from the ground up.

[dj1yfk]

A good starting point would be a look at some implementations of PSK31 programs. I don't know if there are any free programs (meaning: freedom to study the source code) in the Windows world, but there are plenty for Linux/Unix, ranging from very simple (http://packages.debian.org/psk31lx) to very advanced (http://gmfsk.connect.fi/, http://www.w1hkj.com/Fldigi-2.x.html).

A solid understanding of the underlying mathematics and DSP basics will help to avoid a lot of frustration. One excellent and often quoted ressource can be found (and downloaded) at: http://www.dspguide.com/.

[k5okc]

I think the best description is: AE4JY (http://www.moetronix.com/ae4jy/files/pskcoredll133.pdf).