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Flying
erase head
Video recorders record on video tape in a
pattern called helical scanning. The recording is
made by a recording head attached to a rotating
drum that is at an angle to the tape. The figure
below shows the helical pattern the recording head
writes to the tape.
Also
on the tape may be separate audio and control
tracks. This varies from format to format - for
example, 8mm
tape stores audio in the helical part of the
track.
Inexpensive
recording decks use a separate erase head that
erases in a direction perpendicular to the tape
rather than in the helical pattern. This can result
in only part of the track being erased, which
causes the synching problems and color banding at
edit points common with inexpensive
VHS
decks. A flying erase head is mounted on the drum,
and erases the helical tracks correctly and makes
clean edits possible.
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The
helical scan pattern. Cheaper recording
decks have an erase head which is
perpendicular to the tape, as shown here.
Better decks have an erase head which is
parallel to the scan
pattern
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