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3-2-4. Drive Unit (CDM-57)
• P-CAV DRIVE
By using latest P-CAV (partial CAV) technology, the CDM-57 real-
izes data transferring with variable transfer rate, from 12* (inner track)
to 24X (outer track).
Achieving 20X (3000kBytes/s) average data transfer rate, the CDM-
57 shows excellent performance.
* In the case of scanning velocity 1.3m/s and 60 min. disc reading
FUNCTION OF PARTIAL CAV
CDM-57 (Drive Unit) features Partial CAV capability for Maximum
Speed, taking advantage of Wide Capture Range capability of PLL
(Phase Locked Loop) in its fastest speed mode.
Spindle Rotational Speed
Spindle Rotational Speed
12X–24X CAV area
6000
5000
0
Address on the disc (min)
Spindle Motor rotates constant at approximately 6,000 rpm, equal to
the rotational speed of 12X CLV on the innermost track, in the area
between the innermost track and the point of approximately 39 min-
utes. (CAV area)
Data Transfer Rate
Data Transfer Rate (x 150kB/s)
24X
12X
0
Address on the disc (min)
In the disc area outside the fore said 39 minutes, the spindle motor
follows the spindle speed curve of 24X CLV (CLV area).
24X CLV area
39
60
Average 20X
39
60
• CANCEL FUNCTION OF INBALANCED DISC
1 Adoption of VCAN (Vibration Cancel) motor for the
spindle
CDM-57 has new type of spindle motor that cancels imbalance of a
disc automatically. Thanks to the new spindle motor, self-vibration
of the drive is reduced when the drive reads the imbalance disc.
2 Adoption of shock sensor
CDM-57 has a feature that can detect excess vibration caused by
imbalance disc. Thanks to this feature, CDM-57 automatically re-
duce it's spindle speed to 8X–20X CAV mode when such imbalance
disc is inserted. It contributes to less vibration, less audible noise,
better readability and provides comfortable operating condition to
end user.
• CAPABLE OF READING CD-RW DISC
CDM-57 has the capability of reading CD-RW disc. CDM-57 can
automatically adjust RF amp gain and error amp gain to the proper
value for CD-RW disc, when CD-RW disc is inserted. But CDM-57
can read CD-RW disc only at 4X maximum speed.
• FAST ACCESS TIME
Random access time is Typ. 90 ms at P-CAV mode, which reduces
vibration of spindle rotational speed so that the access time improved.
• POWER SAVING MODE
CDM-57 has a power saving mode. If any command which requires
disc access (such as READ of SEEK command) is not issued to the
drive for more than the inactivity time, which can be set by mode
select command, the drive goes into "standby mode" automatically.
Any command that requires disc access can resume the drive from
"standby mode".
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