Sharp RX-P1H Technisches Handbuch Seite 10

RX-P1H
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1-5. Tracking
The reproduction (playback) signal from two heads, A and B, is
amplified by the high-frequency amplifier through the rotary
transformer. Figure 1-6 shows the signal waveforms, one from
head A and another from head B.
The reproduction signal contains wide-band frequency. Its
maximum frequency is 3.13 MHz. The two heads, A and B, are
fitted to the drum, opposing to each other at angle of 180°.
The tape is wound around the drum, covering its 135° area.
When the drum makes 1/2 turn (180°), output is given for 135°
of turn. Although the initial music signal is continuous analog
signal, it is digitized. Consequently, data for specific time is
timebase-compressed or expanded when it is recorded or
reproduced.
A HEAD
RF SIGNAL
TSCK
The track pitch of DAT in the standard mode is about 13 1m. To
trace the track having a size of 13/1,000 mm, the tracking servo
system, called the area division ATF, is used. This system is
designed so that signals of the left and right tracks are caught,
and centering is executed by comparing the levels of signals.
Since the frequency of ATF pilot signal is as low as 130 kHz, the
signal of adjacent track can be detected by crosstalk. The ATF
signal is provided in two places, namely at both sides of track.
As tracking is performed based on the recorded signal,
satisfactory compatibility and high accuracy of mechanism are
obtained. In the after-recording mode the tracking signal ensures
highly accurate rewriting.
30msec
CYLINDER ONE ROTATION
B HEAD
Figure 1-6
f:ATF PILOT SIGNAL
€130kHz)
olf
PILOT SIGNAL OUTPUT
IN CENTERING STATE
PILOT SIGNAL OUTPUT
IN OFF-CENTER STATE
Figure 1-7
—~12-