Well the way it works, and this is what confused me and alot of people is that of course you can't have fractional frames so how can you have fractional frame rates.
It's better to think of it in terms of 'display a frame every x".
If you think about it in nanoseconds(1 billionth of a second).
23.976 = 1 frame about every 41708ns
24 = 1 frame about every 41666ns
29.97 = 1 frame about every 33366ns
30 = 1 frame about every 33333ns
So 24fps & 30fps display frames slightly faster then their NTSC counterparts. Also you may record a few extra frames if you're recording using 24fps or 30fps
So technically even a old reel based machine could acheieve 23.976 or 29.97 if it was adjusted properly.
~klinky