Direct Digital Synthesis

In that case, have a look at this tutorial from Analogue devices, it is very comprehensive.

http://www.analog.com/static/imported-files/tutorials/450968421dds_tutorial_rev12-2-99.pdf (http://www.analog.com/static/imported-files/tutorials/450968421dds_t)

you better copy/paste this link.

Bear in mind the method of virtual LUT and its phase resolution. the way a limited LUT can be interpolated resulting in a virtual very large LUT.

Notice the concepts of phase resolution, amplitude resolution, etc and the way LSBs of accumulator are discarded.

Note also the phase continuity of dds when changing tuning. However many people are not aware that this continuity only holds one side of frequency polarity i.e. changing from + to - or the reverse breaks the phase.