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"DSP" at Wikipedia

Efficient algorithm to compute a DFT for an arbitrary set of frequencies

I developed this specific algorithm for one of my projects. Similar to "Goertzels Algorithm" it should be used to compute the DFT of a small, limited number of frequencies rather than the whole spectra.


Direct synthesis of an arbitrary waveform signal

The principle described provides an easy way to design an arbitrary digital waveform generator that can be used up to very high frequencies with comparably low noise generation. For certain applications it provides a good alternative to the standard DDS-approach.

P.S. Sorry, but the abstract is (so far) only available in German.


Number puzzle

"Number" is an entertaining by-product of one of my DSP-projects. It was written in MS-EXCEL VBA (sorry, I've yet to find the time to transfer it into some decent programming language ;-) The underlying idea is to generate what is known as a "Magic Square" based on variations of a single numerical sequences. In DSP-language the result of those variations is a multitude of different spectra, all having the same power. Once the algorithm has been unveiled, filling the square becomes very easy.

Have fun!

Numbers.xlsm (Excel 2007) Numbers.xls (Excel 97-2003)