Yamaha CRW2100SX - Manual (Page 11)

Introduction
2
*1 Pure-Phase Laser System (patent applied for)
Technology that reduces phase interference of the laser beam, so that it shines accurately on the disc.
*2 Jitter value
An important measure of recording quality. This has been improved 25% compared with Yamaha models
not using this technology.
*3 Running OPC (Optimum Power Control)
CD-R/RW discs vary by manufacturer in their recording characteristics, and the laser output required
to write data differs by disc. Running OPC is technology that solves this problem by automatically
adjusting the output of the laser according to the material of the disc on which data is being written.
*4 If you attempt to write at 16X or 12X speed but the CRW2100SX drive detects that the quality of a
target CD-R disc and other things are inappropriate for such speeds, the drive will automatically slow
down the writing speed optimally for the disc.
About Partial CAV (Constant Angular Velocity)
Writing to a CD-R disc is normally done using CLV (Constant Linear
Velocity) method. In this method, the disc rotation speed will be so adjusted
as to keep a constant data transfer rate at any portion of the disc. In other
words, the disc rotation speed will vary in CLV writing.
In contrast, CAV (Constant Angular Velocity) method uses a constant disc
rotation speed at any portion of the disc whereas the data transfer rate will
vary. Because CAV method has an advantage to largely increase the data
transfer rate with a minimum load to the drive’s mechanism (compared to
CLV’s rotation speed adjustment), many of current CD-ROM drives use CAV
method.
CD formats define the constant linear density of written data (data should be
written onto the disc track in the constant pitch) so that amount of recorded
data per disc rotation will increase as the writing point moves from the inner
to the outer. In other words, in CAV writing the outer portion has an
increased data transfer rate.
The CRW2100SX drive uses CAV method in the inner portions as well as
CLV method in the outer portions (Partial CAV) in order to enable up to
16X-speed writing. The drive will control the disc rotation speed to start
writing at 12X speed in the inner portions, gradually accelerating up to 16X
speed and maintaining 16X speed in the outer portions.