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RX-P1H
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1-3. Tape Format
The recently standardized and marketed model has the rotary
head system (R-DAT) which is designed so that the head tilted
slightly with respect to the tape travel direction as with VTR is
rotated with high speed to record and play back. Digital signals
are recorded on the tape in diagonal direction.
Tracks are
arranged tight. This recording system is called the guardbandless
recording system.
with respect to the vertical of track whereas the head B gives
negative (a) azimuth. Therefore, even when the head A enters
into the B track area in playback mode, high-frequency signal
crosstalk does not occur because of azimuth difference of 2a.
Figure 1-4 shows the tape format. The tilt angle (@) of track is
determined by the inclination of drum and tape travel speed. The
track tilt angle of DAT is 6°22'59.5". The normal tape speed is
8.15 mm/sec, about 1/6 of tape
travel speed of compact cassette tape.
This enables more signals to be recorded on shorter tape.
However, if the head enters into the adjacent track area, when
tracing a track, crosstalk occurs, resulting in noise.
So as to prevent the crosstalk, the azimuth recording system is
adopted.
The drum of DAT has two heads, A and B. While the
drum is rotating, they record signals on the track alternately.
Namely, the head A records signals, giving positive (a) azimuth
TAPE TRAVEL
p
DIRECTION
=
Vt
OPTIONAL
TRACKI
TRACK
GUARD
-
20°
B
+AZ IMUTHo
20°
—AZ
IMUTHo
TRACK
GUARD
REFERENCE
EDGE
OF
TAPE
L
I
Figure 1-4 Tape format
Item
Unit
Symbol
Normal track mode
Wice track mode
Normal speed
Half-speed
Tape width
mm
A
[36.1
Tape speed
mm/sec
Vt
8.150
4.075
12.228
Track pitch
|um
P
13.591
20.41
Track angle
8
6°22'59.5"
6°23'2).4."
Track length
mm
L
23.501
23.471
Head azimuth
a
+ 20°
Effective record width
_|mm
WwW
2.613
Optional track width
mm
R.C
0.4
Table 1-3
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