Normally, when the camera is in 720P24 mode, the CCD clocks at 48fps but only writes 24 of the frames to tape (every other frame sent from the CCD.) The same happens in 720P30 mode, but the CCD clocks at 60Hz and only writes every other frame to tape with repeat frames.
When you turn on "SMOOTH MOTION" the same amount of frames are written to tape, but instead of simply skipping the in-between frames, they are combined.
Therefore, of the 48fps captured from the CCD, frames 1 & 2 are "superimposed" and written to tape as one frame, frames 3&4, 5&6, etc in that pattern.
Here's some tests I shot. Watch them frame by frame to see the results.
