Sharp DV-500D Technical Manual page 19

3-4 8/16 Modulation
When the part without a pit continues to track a disc, it becomes difficult to create a laser spot to
follow based on a pit. Also, it is difficult to judge how many 0s and 1s are being followed.
Therefore, it is necessary to limit the length of the part without a pit on the track. That means, it
is necessary to limit the succession of 0s and 1s.
8/16 modulation converts the original 8 bit data into 16 bit to limit the succession of "0s" or "1s"
from 3 to 11. Also, NRZI modulation makes both of the pit edges a "1". With this, code reading
and recording density accuracy increases. (See below)
0 0 1 1 0 1 0 0
19
0 1
Before conversion
After conversion
DVD-Series