The display of a video frame
as two successive fields
, each containing half the picture information.
This system arose from limitation of early video display units
. Each field
is scanned onto the CRT
from top to bottom, in a series of horizontal lines
, (scanned left to right). The frequency
at which these lines are scanned is reduced by a factor of 2 through the use of interlacing, thus lowering the design demands on the drive electronics.