These recorders are divided into two classes, single and dual head machines.
Single-head recorders use either the alpha or omega type of wrap (fig 1-2).
Two popular methods of tape transport in helical scan machines
The single-head format is used with a processing amplifier when a break in
the information can be tolerated. The rotational velocity of the record/ produce
is normally governed to make certain that this dropout video signal is shifted to
the lowermost section of the screen, thus making the dropout unobserved.
method of recording is sometimes referred to as a full helical scanning system
complete spiral around the rotating head.