Direct Digital Synthesis

For a while i been exploring the several possible ways of generating sound with the Atmega 328.
So one of the good ways is always to start from the basic things !

Direct digital synthesis (DDS) is a method of producing an analog waveform— Sine wave, Square wave or Triangle are the most used and required— by generating a time-varying signal in digital form and then performing a digital-to-analog conversion.

Square, triangular, and sinusoidal waves from a DDS

There are many possibilities for frequency generation , ranging from phase-locked-loop (PLL)-based techniques for very high-frequency synthesis, to dynamic programming of digital-to-analog converter (DAC) outputs to generate arbitrary waveforms at lower frequencies.
A good example can be a signal generator, an essential tool in the arsenal of any electronics geek !!
It is also widely used in Radio frequencies, and modulation  .


So i came across this Article on Direct Digital Synthesis. http://lionel.cordesses.free.fr/gpages/DDS1.pdf

 Also check these webcasts from Analog Devices...   http://www.analog.com/en/content/WC_FUN_PLL/webcast.html
and
http://www.analog.com/en/content/WC_FUN_DDS/webcast.html

Last but not least, the good ol'Wikipedia
http://en.wikipedia.org/wiki/Direct_digital_synthesizer