Learning Event 8:
DESCRIBE CONSTRUCTION PRINCIPLES OF VARIOUS TYPE HEADS
1.
Construction principles of various type heads.
a. Basically, all heads are constructed on the same principles, that is two
identical core valves made of very thin laminations of special magnetic alloy.
Each of these core valves is wound with nonmagnetic separators and a minute gap at
the front. The front part of the head traces the tape.
b. The video helical scan record/playback head is different from the audio
head in appearance and physical dimensions.
In Figure 1-5, an enlarged
illustration of 1-inch wide tape, you received an idea of the pattern recorded by
the video head. Figure 1-17 illustrates the manner of placing all information by
means of the various heads on the tape.
2.
Figure 1-19 illustrates the guard bands as well as audio control, cue, and
video. The guard bands serve to prevent crosstalk between tracks. You will note
the small width of the video track, .006 mils, and the smaller guard bank of .0027
mils.
a. You will also note in this illustration that the main audio track is seven
times the width of the video, or .043 mils. Even the cue audio track is twice as
wide as the video track, or .012 mils.
b. Also, the control track is more than three times as wide as the video
track, or .020 mils.
These comparisons will give you an idea of the precise
construction of the video head.
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