The recent thread on accurate VFOs got me looking at numerically controlled oscillators, tasks usually subsumed to DSP type engines, like the AD part I flagged up in the thread.

What kind of algorithm do these things employ ? I have also heard NCOs referred to as "phase-increment oscillator", but seen no implementation details. What limits their frequency resolution and maximum/minimum o/p frequencies ?

I am sure our resident VHDL gurus will have some comments.

Steve